I partially maintain a GitHub project with ~1500 stars, many of my users are not very technically skilled. I rarely encounter entitled/mean/crazy people - we probably average one obnoxious contributor a year, two or three if you count the ones who go away when you politely tell them it's not going to happen. I get a lot of PRs and reasonably well-written issues from users whose profiles indicate it's their first contribution.

I think a lot of this has to do with the effort you put into community management. We put tons of energy into making it easy to make good contributions: PR/issue templates, we're on slack, we respond to emails, we make it as easy as possible to get your code in as long as it passes tests. It's a lot of effort and I can't imagine doing it for something that was just a personal project, but I think that's how the bigger projects deal with it.