People can be terribly tribal.I must say I don't buy this resentment of "the wrong kind of cyclist", who wears the wrong kit. CC can be terribly tribal.
More people cycling is a good thing. It means the person driving the white van/4WD panzer/LGV/any little car has a greater chance of knowing what it's like to be on two wheels and, hopefully, will be a little bit more careful. I guess that's tribalism working in a good way.