"Shouldn't have shared his opinion" and "should have shared his opinion in a different way" are two completely different things, and I don't see many people saying the first.
Can someone produce a "diversity culture" critic (for lack of a better term) who provides a good example for Damore? One that is well received across the board?
A big four-paragraph disclaimer at the beginning would've been a big waste of everyone's time, and it could just as easily be interpreted as a sign of hostility or malfeasance. If people want to dislike something, there is an infinity of potential nits to fixate on.
I've always been brash so I've been through the "delivery ringer" many times. The conclusion I've reached is that frequently, the only way to avoid it is to be so opaque and listless in your communication that people aren't sure what you meant.
If you say something people don't like in a non-ambiguous way, they will be mad, and they will insist on finding a reason to dismiss it.