Last week a controversial internal memo written by a concerned Google employee was going viral within the company. The memo, titled "PC Considered Harmful" and since dubbed "the Google manifesto" on social media, argued two points: First, that Google has become an ideological echo chamber where anyone with centrist or right-of-center views fears to speak their mind. Second, that part of the tech industry's gender gap can be attributed to biological differences between men and women. The person who wrote the memo has since been fired, but the internal tussle has revealed one more thing. The Inc reports: The contentious internal discussion revived a concern dating back to 2015: An unknown number of Google managers maintain blacklists of fellow employees, evidently refusing to work with those people. The blacklists are based on personal experiences of others' behavior, including views expressed on politics, social justice issues, and Google's diversity efforts. Inc. reviewed screenshots documenting several managers attesting to this practice, both in the past and currently, explicitly using the term "blacklist." The screenshots were shared by a Google employee who requested anonymity due to having signed an NDA. In additional screenshots, one Google employee declared his intent to quit if Damore were not fired, and another said that he would refuse to work with Damore in any capacity. A Google spokesperson told Inc. that the practice of keeping blacklists is not condoned by upper management, and that Google employees who discriminate against members of protected classes will be terminated. It's not clear whether that principle applies in Damore's case. Although political affiliation is a protected class according to California labor law, the views expressed in the manifesto and echoed by others who oppose political correctness do not seem to merit legal protection.