There's a very big range between "behave like a 10 year old school child on their first day at school" and "get absolutely plastered, and start sexually harassing your neighbours". And no, I'm not making things up, I've seen this happen, personally. If the latter is a 10, an establishment could kick anyone out above the level of 8. Get drunk, misbehave to a point, break a pint or two throughout a year, that's fine.

The problem is, you can't objectively measure the unacceptableness of particular behavior. You can't tell a guy "you see, our unacceptableness meter shows 8.1 unacceptableness units, while our limit is 8, so you're out". It's all relative to social dynamics of particular group. Learning and following those dynamics costs energy, and if I'm spending my energy on something, I want a return on my investment. That's why I don't hang out with random people, but rather with people whose views on social norms align with mine.