@pzmyers you say regressive social tendencies but if also like to add reactionary to that mix.
I think these modern, in the words of Mikhail Bakunin, "charlatan savants" innately and intimately understand that atheism is a rejection of hierarchy as well as a deity. If someone holds that one set of people is superior to another, a liberal, progressive or leftist perspective is anathema so you take actions to protect that hierarchy....by dismissing Feminists...engaging in islamophobia...etc.