"the reason they feel so threatened is that they really, really, really want to oppress minorities"
I'm not sure that's right at all. I think they feel threatened because they feel oppressed THEMSELVES.
Surely most people actually want to improve their *own* situation much more than they actively want to worsen someone *else's* situation. They may be callous as to whether they *do* make things worse for someone else, but it's not the primary motivation.