I'm personally very worried about sentiments like the one you express. The smug complete dismissal of another's viewpoints, complete refusal to even just listen, generalizing over all people with the same ideas...

Opinions like being in favor of Brexit are not in any sense as fundamentally objectionable and unacceptable even for disucussion as, for example, nazism or racism. Political divisiveness is a significant issue, and behavior like this is only going to make it worse.