If people cannot argue fruitfully about questions that are part of their identity (and I agree with this premise), then it follows that for one to win politically (or convert them), the trick is not to convince people that your views are correct, but rather to convince people that their identity is threatened and that them maintaining their current identity (whatever that identity may be—and perhaps vagueness is key…
> Why are people seemingly so drawn to identifying themselves as anything at all? This is biologically preconditioned. We have brain wiring for identifying "Us" and "Them". BigThink put up a compilation video [1] on this topic. [1] - https://www.youtube.com/watch?v=14XSzWT4vI0
Edit: So it's a cultural rather than biological precondition. ( If a precondition at all. )