Kelly Ellis would like an apology.

The former Google software engineer felt a mix of emotions as she watched the massive walkouts protesting sexual harassment at the corporation’s offices across the globe on Thursday. She said it was moving to see thousands of employees demonstrate, but that it was hard not to feel frustrated and stuck on a nagging question: what took so long?

She also wondered if Google would ever say sorry.

Ellis first spoke publicly about experiencing sexual harassment at Google in 2015. Last week, Google came under global scrutiny after the a New York Times investigation revealed that the corporation gave $90m to a top executive after determining that sexual misconduct allegations against him were credible.

When Ellis tweeted her accusations, it was also long before an Uber scandal sparked a mainstream debate about discrimination in Silicon Valley, and before the #MeToo movement exposed rampant sexual abuse in many industries.

Ellis, who is taking Google to court on allegations that the company systematically underpays women, spoke to the Guardian Thursday about this week’s unprecedented global protests and how she hoped to spark reforms through her class-action litigation.

“It’s both vindicating and frustrating,” Ellis said of the protests, which workers organized in response to the recent revelations about the company’s treatment of women who speak up about harassment. “It’s this weird combination of, ‘Oh, at least I wasn’t the only one.’ And, ‘Oh God, I wasn’t the only one.’”

“It definitely brings up those memories,” she continued. “It does bring back some of that anger, but I’m really glad these employees are standing up.”

Ellis, who was first hired in 2010 as a software engineer for Google Photos, eventually discovered that other male software engineers who were less qualified or at the same level were placed and promoted into higher positions than hers, according to her lawsuit, which could affect more than 8,000 current and former employees.

Google “segregated” her and other women into less prestigious and lower-paying engineering roles then men, and she quit in 2014 due to the “sexist culture at Google”, the complaint said. A year later, she made headlines when she alleged that she was sexually harassed by her male superiors and faced inappropriate comments, and that Google failed to support her.

Ellis’ claims resembled the theme of allegations uncovered by the New York Times – that men accused of wrongdoing don’t face consequences while women who speak up are sidelined in their careers.

“It is just so unfair, and it’s so frustrating especially when you have a financial loss on top of that situation,” she said, adding: “A $90m payout was something that seemed to make a lot of Googlers wake up.”

Ellis also argued that the culture of sexual harassment was linked to the alleged pay disparities at Google. The US Department of Labor has said the wage discrimination is extreme.

Google workers hold a walkout at the Googleplex offices in Mountain View. Photograph: Stephen Lam/Reuters

Ellis said that harassment can force people to go backwards in their careers when they transfer out of departments.

“So these situations, especially where there is an imbalance of power, definitely can affect the victim’s ability to perform their job and advance in their careers within Google,” she said, adding that women are afraid to speak up because of potential professional consequences. “When the person harassing you is someone who has a lot of influence over your career trajectory, that’s probably the biggest reason people don’t want to report.”

The walkouts and the stories from other women at Google have been validating, Ellis added: “I wasn’t just mistreated as this isolated incident. It was this pattern of how they reacted to sexual harassment at Google.”

Google’s CEO, Sundar Pichai, emailed staff saying he would support the protests, a move that drew criticisms from some workers who accused him of trying to take credit for the demonstrations and counter the negative press, without committing to substantive changes.

“You’re the one being protested,” Ellis said of Pichai, adding, “Google is hesitant to admit any wrongdoing. They owe every one of the women mentioned in that [New York Times] story an apology. They owe me an apology. Someone has to open up and admit some culpability here for what happened.”

Although Larry Page was Google’s chief executive at the time the company allegedly agreed to the $90m payout, Pichai was responsible now, Ellis added: “He’s where the buck stops.”

Speaking at a conference after the protests, Pichai said: “Moments like this show that we didn’t always get it right, and so we are committed to doing better.”

Google has repeatedly argued that it has closed its gender pay gap – a claim that Ellis and her attorneys hope to disprove through the class-action.

“The reason we are doing this is because I don’t think Google is going to fix pay inequality on their own. They’ve been really resistant,” Ellis said.

Ellis said she was also encouraged to see discussions of unionization as a next possible step of the movement and that she hoped workers at other corporations would be motivated by the Google events: “There are so many issues that technology workers should be making their voices heard on, including around ethics of the technology we build and how it should be used.”