You use racism as an example but what Damore said was not racist, he didn't use any epithets, he isn't a white supremacist. It's really odd that you try to lump him in with them.
Since you missed it, the point was this: it's irrelevant that he posted it on a company board that was asking for opinions, so stop trying to use that as a defense. If you want to defend what he said, go nuts. We can argue the merits and whether Google overreacted. Just don't whine, "but they asked his opinions!" as though that's some sort of shield.
The actual problem, as I stated, is that Google accepts extremely vitriolic commentary from the left (at work!) but even Damore's relatively tame memo caused him to be fired.
Refer to Damore's lawsuit for many examples of the the extreme rhetoric that is allowed within Google corporate.
Conservatives at Google know this all too well. They've seen eng-misc and memegen and know that there is a very limited spectrum of "acceptable" opinion. The problem wasn't that political content was posted, as that happens all the time, it was that it was political content that was deemed to be "wrong."
Ask conservatives/GOP supporters how they felt after Trump was elected and the TGIF presenter tried to comfort the audience, which they assumed all voted for Clinton...talk about ostracizing your workforce that may hold a different private opinion
If my boss says, "Hey deong, what do you think about black people?", that's not a get-out-of-jail-free card for me to start dropping n-bombs. There's one answer you're allowed to give to that question, and it's not because there's some conspiracy to oppress dissenting opinions. It's because there are extremely reasonable standards for employment that include not shouting racial epithets and white supremacist propaganda. Being asked your opinion doesn't change the rules.
Damore was certainly less inflammatory than that, but the point remains. You can argue that his opinions didn't warrant firing, but there's no reasonable way to argue that because he was responding to requests for comment, it's unethical or otherwise shady to hold him accountable for those comments.