I would say yes, given that it's such a simplistic framing of the situation - the impression given (whether intended or not) is ah, those liberals and socialists with their multicultural dreams! When will they wake up and see that it doesn't work! The response was fine

And the original post that referred to "neoliberalism" as the root of all our problems isn't being just as simplistic in their reasoning?

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)