We know that "Damore wrote an essay basically arguing women and minorities should be incapable of joining the software profession based on their genetics." is factually false, considering that what should it be called if not libel?

> Google, a private corporation

Which by the way told its employees that they were free to publish their opinions and Damore acted on that premise.

I often find that those whose favorite rethorical tool is lying much prefer to slander their opponents rather than attempt to refute their points.

You did understood he was referring to you, right?

free speech gives you certain right to say what you want to say, and express your opinion. It even lets you give your opinion on other peoples opinions.

It doesn't allow you to state as fact that someone holds an opinion that they do not. You can express an opinion, but there are limits on stating falsehoods, especially wrt other people.

you say "encounter an opinion they happen to disagree with", implying your statement about the memo is just your opinion, but you didn't say it in any way that suggests it was that subjective; and, making any unsubstantiated claim about a person is on shaky ground even if you did make it clear it was just opinion.