human beings need roughly value homogenous peer groups in order to activate the part of the brain that says "these are my allies". If that part of the brain pretty much never fires it will lead to the ennui, apathy, negativity and judgment mentioned here. We've been brainwashed to think diversity good, and it is, but it is not a monotonic good. There are lots of negative connotations around communities that share and reinforce strong values. They are often perceived to be xenophobic, and of course they sometimes are, but it is not a fair universal judgement.