It's OK to be skeptical. But when evidence is presented that it's not the case, and you are doubling down by denying it, it's not being skeptical anymore. It's refusing to accept the facts since they don't fit your preconceptions.
> We mainly don't know what happened at Google.
We don't, beyond public evidence (including one in the lawsuit and outside). But that evidence we do have, and it does not align with your presumption that Damore was poor performer, unless you accept a completely invented premise that all his peers in Google somehow colluded to fake his reviews and performance evaluations, but he was still unhappy and decided to push the diversity angle to achieve... I don't know what, getting fired from a job where everybody, according to you, were going out of the way to make him happy? I don't think this is a workable hypothesis, and certainly not one that bears minimal skeptical scrutiny.
You can't be called "skeptical" if you only mistrust evidence which does not fit your preconception, but accept and even invent one that fits one. That's not skepticism, that's agenda.