Neoliberalism is a phenomenon with quite well defined characteristics, so no.

'Lefties' used to dismiss another's point of view as invalid withiut actually explaining why is just baselessly tribal and antagonistic.

Well, for the very reasons discussed here, that's debatable due mainly to it being turned into a snarl word, mainly by those on the left-hand side.

But yeah, definitely so re your second point, it is needlessly antagonising, and destroys measured political discussion (as it always has and always will)

Oh, no doubt about that, it's distinctly unhelpful in any political conversation (unless the aim is to deliberately trying wind up the other person in the conversation)