There are rules the community follows to maintain a certain level of social cohesion, which in turn aides us in the pursuit of rationality.

How is that demonstrated?

Those rules are rarely discussed outright, at least not comprehensively.

I'm pretty sure if I started posting half of my comments in pig-Latin or French or something, for no apparent reason, and refused to explain or stop, I'd be asked to leave fairly quickly, though. That all communication will be in plain English unless there's a reason for it not to be is one example. I'm sure there are others.

It's demonstrated by the fact that you can up/down vote and report anyone's posts, and that you need a certain number of upvotes to write articles. This is a method of policing the discourse on the site so that social cohesion doesn't break down to an extent which impairs our discussion. These mechanisms "reinforce correctness," in your terms. So I'll ask again, can we do away with them?

I don't think humanity follows obviously from rationality, which is what I meant about rationality being a means rather than an end.