I often find that the usual so-called defenders of free speech do not hesitate for one moment with that libel charge whenever they encounter an opinion they happen to disagree with.
> 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.
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.