I don't agree with Damore's message. But Google cultivated an environment were open discussion were encouraged. So firing him for stating his opinion is truly, hypocritical bullshit. People should get fired for not doing their jobs -- not for writing what they think. And I also want to say that before you blame "the Left" for Google's behavior... Had he been fired in "Socialist Europe," the firing would have been dec…
It's worth keeping in mind that Europe certainly isn't one place when it comes to labour regulations. Some places you barely fire people at all (prevalent in the South, apparently getting reformed in France) and in some places it is significantly easier (several countries in the North), if not quite at will. The "easiness" generally has to do with the burden attached to showing insufficient performance.
Even if the employer could show that the manifesto caused a toxic work environment (hard), and that that was also Demore's intent (even harder), the employer would also need to show that they had tried to resolve the situation with other means. For example, by asking Demore not to publish similar manifestos in the future. Had he then refused to comply, their case would have been stronger.
Not even the examples I gave -- a cock not able to boil eggs, a train conductor always oversleeping or an active member of a Nazi party -- are completely clear cut in all countries. And Damore's manifesto is very, very far from it.