I think you're too eager to throw personal attacks on those who raise valid points that are you feel are uncomfortable to address.
You should be aware that engineering is a social activity that requires hard skills. In any project that employs more than one person, you need to be able to interact with others. This means being able to effectively address and interact with others around you.
If you give anyone a choice, anyone at all, on who they work with, they will of course favor those who they are able to effectively interact with.
This is not bigotry, is it?