Perhaps the answer is more ignorance. I doubt most of the political groups any of us worries about is actually as large and as ill-intentioned as we imagine, but rather than have no idea we always know just enough to feel in danger. Feeling in danger, we seek to control first and understand later, and that makes our political neighbours feel threatened, and so it goes until the centre cannot hold.

Perhaps the paradox of tolerance requires a deliberate agnosticism about how people unlike us live, a turning away from information that would turn us reactionary if we only had part of it. That used to be the default in an era of slow communication, but it could be cultivated deliberately if it's what's needed.