On Friday night, Vice's Motherboard reported that 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 his or her mind. Second, that part of the tech industry's gender gap can be attributed to biological differences between men and women.

This news caused an immediate and lasting uproar, both within Google and on public discussion forums like Twitter. The dismay and outrage -- and then the inevitable counter-outrage in response to the initial outrage -- heated up further when Gizmodo released the full text of the open letter. Critics have primarily focused on author James Damore's implication that women are less prevalent in software engineering and leadership roles because of the unequal distribution of innate characteristics like spatial reasoning and neuroticism. Update: Damore has since been fired, Bloomberg reported.

Within Google, a few sympathetic employees were dismayed to see Damore so vehemently criticized by their colleagues. In a poll distributed on a mailing list dedicated to discussing the manifesto, opinion broke down differently than it did in non-anonymous Google Plus posts:

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.

Indeed, Google's decision to fire Damore suggests the company concluded they don't, although its slowness in acting suggests it was not an easy call. According to New York Times reporter Daisuke Wakabayashi‏, Damore "said he will likely take legal action against the company."

Damore's manifesto wasn't classic political speech, said Harmeet Kaur Dhillon, an experienced business and labor lawyer. Rather, it's what she called "controversial speech," not unlike any other opinion that might anger co-workers. She added, "These are not insane views that he's extolling here -- they're [just] out of the mainstream. He's entitled to hold views that are inconsistent with the mainstream."

As to whether Google had an obligation to fire Damore, "The question is whether he's acting on those views in a way that violates discrimination law," Dhillon said. She noted that although California has stronger labor protections than most other states, "The cases involving political speech are much more cut and dried," involving conventional political activities like voting for a candidate or running for office.

Editor's note: This article has been updated to reflect the fact that Damore has been publicly identified as the manifesto's author and fired from Google.