Republican lawmakers continued to grumble over Facebook's treatment of Trump-supporting sisters Diamond and Silk to the company's CEO Mark Zuckerberg, during his second day of Capitol Hill testimony.

Rep. Bill Long, a Missouri Republican, hauled out a picture of the two women and asked Zuckerberg to identify them.

'I believe that, is that Diamond and Silk?' Zuckerberg asked.

Long said it was. 'That is Diamond and Silk, two biological sisters from North Carolina, I might point out they're African-American, and their content was deemed by your folks to be "unsafe,"' Long said.

'Diamond and Silk have a question for you. And that question is, "What is unsafe about two black women supporting President Donald J. Trump?"' he continued.

A number of Republican lawmakers asked Zuckerberg questions about the Trump-supporting sisters over his two days of testimony on Capitol Hill.

'Well Congressman, nothing is unsafe about that,' Zuckerberg answered.

Facebook CEO Mark Zuckerberg sits on Capitol Hill for day No. 2 of testimony, this time before members of the House of Representatives. He was asked by multiple Republican members about the treatment of conservative video bloggers Diamond and Silk

Rep. Billy Long, a Missouri Republican, brought up perceived bias against Trump-supporting sisters, Diamond and Silk

Rep. Billy Long even went as far as to have an aide hold up a picture of the two women and asked Facebook CEO Mark Zuckerberg who they were. 'I believe that, is that Diamond and Silk?' the 33-year-old CEO answered

Rep. Joe Barton asked a constituent question to Facebook CEO Mark Zuckerberg: 'Why is Facebook censoring conservative bloggers such as Diamond and Silk?'

Facebook CEO Mark Zuckerberg said the warning given to Diamond and Silk was 'an enforcement error'

A number of lawmakers have complained over Facebook's treatment of Diamond and Silk, which the company has said it's remedying

Rep. Joe Barton, a Texas Republican, held up his phone and told Zuckerberg he was going to ask him a question that someone had submitted to the congressman's Facebook account.

'First question: Please ask Mr. Zuckerberg, why is Facebook censoring conservative bloggers such as Diamond and Silk? Facebook called them "unsafe" to the community. That is absurd. They hold conservative views. That isn't unsafe,' Barton said reading the question, and adding his own, 'What's your response?'

Zuckerberg explained that his team had made 'an enforcement error.'

'And we've already gotten in touch with them to reverse it,' he said, referring to Diamond and Silk.

Another Congressman, Rep. Fred Upton, a Republican from Michigan referred to the video bloggers as 'Silk and Diamond' and then asked about an incident involving a GOP political candidate from his state who expressed pro-life views, and whose message was deemed a 'threat' by Facebook.

'I'm not sure what the threat was when I read the post,' Upton said.

Zuckerberg said he was unfamiliar with that particular case.

'Unfortunately, we don't always get these things right,' the CEO told the lawmakers, adding that Facebook has 20,000 people to review content posted.

Later on in the hearing on Wednesday, Rep. Marsha Blackburn, a Tennessee Republican running for Senate, asked whether free speech is being censored by the site.

Zuckerberg brought up terrorism as an example of content that would be banned.

'Let me tell you right now, Diamond and Silk is not terrorism,' Blackburn muttered at the end of her time.

Yesterday it was Sen. Ted Cruz who slammed Zuckerberg, accusing the social media platform of being politically biased.

'There are a great many Americans who I think are deeply concerned that Facebook and other tech companies are engaged in a pervasive pattern of bias and political censorship,' Cruz said. 'There have been numerous instances with Facebook.'

Cruz, a former GOP presidential candidate, then brought up Diamond and Silk.

Sen. Ted Cruz slammed Facebook for its perceived political bias against conservatives and asked Facebook CEO Mark Zuckerberg about it on Tuesday

Sen. Ted Cruz pointed out several instances to Mark Zuckerberg (pictured) in which he believed Facebook had displayed overt political bias

Diamond and Silk, who campaigned alongside Trump in 2016, claimed that Facebook slowed down the reach of their popular videos in which the women push pro-Trump messages.

'The policy team has come to the conclusion that your content and your brand has been determined unsafe to the community,' an email from Facebook read, according to the Washington Post. 'This decision is final and it is non appeal-able in any way.'

Facebook has since acknowledged sending the message, but said its contents were 'inaccurate.'

'We have communicated directly with Diamond And Silk about this issue. The message they received last week was inaccurate and not reflective of the way we communicate with our community and the people who run Pages on our platform,' Facebook's spokeswoman Sarah Pollack said. 'We have provided them with more information about our policies and the tools that are applicable to their Page and look forward to the opportunity to speak with them.'

Cruz's criticism went beyond this recent incident, as he cited a Gizmodo article that said that Facebook had routinely suppressed conservative stories from its trending news section, including articles on the Conservative Political Action Conference, Mitt Romney, the Lois Lerner scandal and Glenn Beck.

Facebook, Cruz charged, 'initially shut down the Chick-fil-A Appreciation Day page,' as well as a post from a Fox News reporter, along with some Catholic pages.

'To a great many Americans that appears to be a pervasive pattern of political bias,' Cruz said. 'Do you agree with that assessment?'

Zuckerberg responded by acknowledging that Silicon Valley, located in bright blue California, is an 'extremely left-leaning place.'

However, adding to the list of things he wanted to improve, the Facebook CEO told the senator that one of his priorities was making sure 'we don't have any bias in the work that we do.'

ZUCKERBERG ADMITS THAT FACEBOOK COLLECTS NON-USERS DATA

Throughout his nearly 10 hours of testimony, Zuckerberg was peppered with questions about all sorts of aspects of the social media site.

Rep. Debbie Dingell, one of the final lawmakers to go, was miffed at some of what Zuckerberg couldn't answer, mentioning how he didn't know how many Facebook 'like' buttons were on the internet, and also didn't know what lawmakers meant when they referred to Facebook 'shadow profiles,' a term used in the media to describe the social network's now confirmed practice of collecting data on non-users.

While Zuckerberg said he had never heard of the term 'shadow profiles,' he did admit to Rep. Ben Ray Luján that Facebook collected information on non-users.

'In general we collect data on people who are not signed up for Facebook for security purposes,' Zuckerberg said, explaining that the practice is supposed to prevent malicious actors from collecting the public-facing aspects of users' Facebook profiles, such as their names.

'We need to know when somebody is trying to repeatedly access our services,' Zuckerberg said.

Luján took issue with the practice because non-users currently had to sign up for Facebook if they wanted to see what data of theirs the social network collected.

'You've said everyone controls their data, by you're collecting data on people that are not even Facebook users who have never signed a consent, a privacy agreement,' Luján said, encouraging Zuckerberg to fix the problem.

ZUCKERBERG SAYS HIS OWN PERSONAL DATA WAS IMPROPERLY SHARED

During the five-hour hearing, the Facebook CEO revealed that his own personal data had been included when 87 million or so Facebook users had their data improperly shared with political consultancy Cambridge Analytica.

'Yes,' he answered when asked by Rep. Anna Eshoo, a California Democrat, whether his data was included in the data sold to malicious third parties. 'Your personal data?' Eshoo clarified.

Throughout the hearings, Zuckerberg pushed back on the insinuation that Facebook users didn't have control of their data.

'Every time that someone chooses to share something on Facebook ... there is a control. Right there,' Zuckerberg argued. 'Not buried in the settings somewhere but right there.'

Rep. Michael Burgess also shared the cartoon on Twitter explaining that 'consumers should have the tools and resources they need to understand how to protect their own data'

In one of the odder moments of the day, Rep. Michael Burgess made a point to Facebook CEO Mark Zuckerberg (left) using a Dilbert cartoon about 'terms and conditions'

Beyond the chatter about Diamond and Silk, the hearing produced another odd moment, when a member of Congress shared a Dilbert cartoon to make a point.

CONGRESSMAN BRINGS DILBERT CARTOON TO FACEBOOK HEARING

Rep. Michael Burgess, a Texas Republican, brought the vintage cartoon along with him to make a point about Facebook's 'terms and conditions.'

'I consulted my technology consultant Scott Adams, in the form of Dilbert,' Burgess said.

The cartoon strip shows Dilbert telling Dogbert, 'I didn't read all of my shrink-wrap license agreement on my new software until after I opened it. Apparently I agreed to spend the rest as a towel boy in Bill Gates' new mansion.'

'Call your lawyer,' recommends the small white cartoon dog.

'Too late, he opened software yesterday. Now he's Bill's laundry boy,' Dilbert responded, referencing Microsoft's CEO.

Burgess' broader point, which he articulated in a tweet, is that too few Americans read the 'terms and conditions,' adding that 'consumers should have the tools and resources they need to understand how to protect their own data.'

ZUCKERBERG ASKED ABOUT FACEBOOK PREDECESSOR 'FACEMASH'

Long, who had also brought the enlarged photo of Diamond and Silk, provided another colorful moment at the hearing when he brought up Zuckerberg's earlier creation 'Facemash.'

Long wanted to know if 'Facemash' was still up and running.

'No, congressman. Facemash was a prank website that I launched in college, in my dorm room, before I started Facebook,' Zuckerberg replied.

'There was a movie about this, it says it was about this, of unclear truth, and the claim that Facemash was somehow connected to the development of Facebook, it isn't, it wasn't,' the CEO continued, referencing the 2010 movie, 'The Social Network.'

Zuckerberg explained that he created that website in 2003. 'It actually has nothing do to with Facebook,' he said.

'And you put up pictures of women and decide which one was the better, the more attractive of the two, is that right?' Long asked.

Zuckerberg said that was right.

'Congressman, that is an accurate description of the prank website that I made when I was sophomore in college,' the CEO said, as Long made comments about the website's beginnings.