Four LGBT YouTubers have joined a class action lawsuit suing YouTube for discrimination, deceptive business practices and unlawful restraint of speech.

The 12 complainants in total allege that the algorithm YouTube, and its parent company Google, uses to promote, censor and pair advertising with videos is discriminating against LGBT content just because it is made by and for LGBT people.

The new additions in the lawsuit include Saturday Night Live associate producer Greg Scarnici, independent film-maker Sal Bardo and Stephanie Frosch, a lesbian YouTuber with nearly 400,000 subscribers. The refiled complaint alleges that YouTube is restricting their content and effectively trying to push them off the platform, as well as retaliating against the original plaintiffs after the lawsuit was first filed in August. YouTube and Google have yet to respond to the complaint. The first court hearing is due to take place in December.

Frosch specialises in vlogs aimed at an audience of teenage girls who are exploring their sexuality, with videos on how to come out to your family, and what to do if you have a crush on your best friend. Like fellow plaintiffs Bria Kam and Chrissy Chambers, Frosch claims YouTube’s algorithm demonetizes and age-restricts her videos, even when they feature no swearing, nudity or discussion about sex. Sal Bardo’s video It Gets Better, made as part of a suicide prevention campaign among young LGBT people, was restricted and therefore cannot be viewed by its intended audience.

Bardo wrote last year that “unless you create makeup tutorials or supercuts of cats napping, you’re no longer permitted to earn revenue on YouTube. And if you’re a queer creator who happens to make those kinds of videos, you may not make any money either.” Despite YouTube’s assurances that they would fix the issues in the algorithm, Bardo’s entire channel was demonitized for the month of September.

Online platforms depend on algorithms to police and monetize the vast quantity of content uploaded every day. As the case against YouTube gathers momentum, it raises fundamental questions about the biases that are built into supposedly neutral software, and the possibility that these could result in wholesale discrimination against entire communities.

Decisions on monetization and restriction are made within moments of the videos being uploaded – too soon for any human being to have made a judgment call. The plaintiffs say this has led to a bewildering scenario where they are no longer tagging their videos with anything that mean they could be seen as “gay” by the algorithm, and are self-censoring in the hope of meeting YouTube’s constantly shifting and opaque standards.

Several of the original plaintiffs say they fear YouTube has retaliated against them for being part of the lawsuit. “Our viewership has taken an insane hit,” said Bria Kam, one half of BriaAndChrissy. “Before the suit, we were bringing in around 200,000 views a day. Now we are at around 50,000,” Kam said. Chambers and Kam have been inundated with messages from viewers who claim they can no longer find their content. “I’m not sure what they are doing behind the scenes, but we’re getting tons of viewers saying they were automatically unsubscribed from our channel or that they just don’t get notifications.”

Amp Somers runs a “kink-friendly” sex education YouTube channel. While some of his content is definitely not suitable for under-18s, Somers claims YouTube has placed a blanket age-restriction on even his most harmless content, including a video of him fully clothed, drinking tea. “Since the lawsuit, it’s only getting worse for us,” Somers said. “I’ve spoken to many creators who have the same problems but don’t want to get involved because they fear retaliation from YouTube.”

Chris Knight and his husband Celso Dulay were the first plaintiffs in the case. They decided to take legal action after their request to pay to promote a Christmas special of GNews, their online news show for the LGBTQ community, was immediately rejected by YouTube’s algorithm. When they finally managed to speak to a manager at a YouTube call centre who reviewed the algorithm’s decision, they were told their content was not suitable for promotion “because of the gay thing”. The recording they made of the phone call is a key piece of evidence in the case.

None of the plaintiffs are sure why the algorithm would have a built-in bias against them. Some think it is to appease advertisers wary of being associated with anything on YouTube that could be viewed as controversial. But Kam, Dulay and Somers say they think YouTube is deliberately trying to push original creators out to make way for their mainstream preferred partners.

“I want a working platform where I don’t have to guess if I should stay on it or not. There’s no transparency,” Somers said.

“We filed the lawsuit because we want systemic change,” added Dulay. “If this is your model, be honest with it, so that we all know to leave. But if you’re still operating under the guise of the original mission statement and ethos of YouTube, then fix your algorithm.”