Yeah. I use a self-definition means of determining identity-- Jews for Jesus are Jews because they say they are, even if other Jews think they're insane and missing the point. (It's like using the gender pronoun a person prefers whether or not you would classify the person that way if you didn't know their preference.) Similarly, hate-spewing overly-political fundamentalist Christians are Christians. They may not, in the opinion of other Christians, be very good at it, but that doesn't mean that one can contradict their self-definition. In my culture, that's just rude.