In this case it very much matters whether the beliefs or aliefs are true.
On the contrary, if you're in a situation of collaborating with someone, then it's pretty widely recognized as a bad social habit to be constantly trying to judge them. Even worse if you're judging them on their group memberships (or other generalities) rather than their actual individual performance in the collaboration!
It's impractical to build consensual working relationships with people who notice that you're treating them as inferiors. (Oh hey, are we talking about microaggressions again? Maybe ...)
Have you ever actually worked with people on a coding project? Have you ever worked with idiots on a coding project? It's very important to know who you can trust and whose code has to be double checked. Also I have a question I need to know who I can ask to get an answer and who would simply be a waste of time.
I remember seeing a talk of the concept of privilege show up in the discussion thread on contrarian views.
Some discussion got started from "Feminism is a good thing. Privilege is real."
This is an article that presents some of those ideas in a way that might be approachable for LW.
http://curt-rice.com/quotas-microaggression-and-meritocracy/
One of the ideas I take out of this is that these issues can be examined as the result of unconscious cognitive bias. IE sexism isn't the result of any conscious thought, but can be the result as a failure mode where we don't rationality correctly in these social situations.
Of course a broad view of these issues exist, and many people have different ways of looking at these issues, but I think it would be good to focus on the case presented in this article rather than your other associations.