Claire Stapleton, an employee at Google's YouTube who spearheaded employee-led policy change movements, has left the company after 12 years, citing retaliation by company leaders.

"The heads of my department branded me with a kind of scarlet letter that makes it difficult to do my job or find another one," Stapleton wrote in a note shared on Medium Friday morning. "If I stayed, I didn't just worry that there'd be more public flogging, shunning, and stress, I expected it."

Stapleton, a YouTube marketing manager, quit on Wednesday, she confirmed with CNBC. Her departure comes as some Google employees claim they have been retaliated against for questioning the company's handling of policies spanning anti-harassment to equal rights for contractors.

Google didn't immediately respond to requests for comment.

Stapleton was one of seven Google employees who organized a massive protest, called the Google Walkout for Real Change, in which 20,000 Google employees and contractors in 50 cities walked off campuses last November to protest the company's handling of sexual harassment cases. That resulted in Google changing some of its policies including ending forced arbitration.

Stapleton claimed that while Google publicly praised her and the organizers' work, it was a different story internally, alleging managers retaliated against her and fellow Walkout organizer Meredith Whittaker. Stapleton was demoted and told to take medical leave even though she wasn't ill, she said at the time.

Walkout organizers again questioned the company's public branding this week when YouTube flip-flopped its enforcement of anti-harassment policies for a far-right user who regularly featured homophobic and racial slurs, all while claiming to support LGBTQ employees for Gay Pride Month. Stapleton left that day, though it isn't clear whether the incident had a direct bearing on her departure.

"I hope that leadership listens," Stapleton continued in her Medium post. "Because if they won't lead, we will."

WATCH NOW: Google employees protest the company's harassment policies.