I'm not sure I'd really consider that anti-social behaviour, though the bar shadow boxing when you are there is not ideal of course.

Ultimately you went into a pub at 11.30pm which you acknowledge people go in to drink in due to cheaper alcohol, and unsurprisingly found some quite drunk people.

Sounds like you wanted a nice quiet pub for a catch up, which is of course perfectly reasonable, but that pub probably is not it, or not it at that time (though the couple of times I have met friends there had no issue, though we met much earlier). I am surprised on a Wednesday night there was not room to find somewhere else to sit mind you, though I've only been a few times.