That is strange. When I do interviews, I will look if this is a nice person, if this is a professional person. I don't really think about which "group" they might belong to.

Your definition of what a "nice person" looks like may be predicated on the breadth of your experience with different people. For many (most?) people, the closer someone is to what their friends/family look and act like the "nicer" they are. That's not a condemnation of you or anyone else - it's normal.

I think some humility is in order. It's possible that one is a perfect, unbiased judge of character. On the other hand it's possible that one is just human, with a predilection for equating "like me and my friends" to "nice" or "professional".

It seems not in this case, as this person hired a diverse team as measured by gender, race and sexual orientation. I'd venture there are multiple approaches to seeking interpersonal compatibility and some of those approaches tend to have better outcomes than others. It seems good to try to learn from people who practice those more successful approaches.