Posting a "don't work with Windows" without any thing more. When asked for a backtrace or an explanation, copy/paste without formatting or anything else. Demanding for a feature without making a case for it. Not using any polite or nice phrasing in a thread.
I don't know the best to react to this. Maybe we should just close their issues without any explanation with just a link to a guideline or something. But, when you care about your project, you tolerate the abuse because you truly want to make your project better despite it.
It's like the rude kid of the article suggesting a new rule, but you actually find it's not that a bad of idea and deserve some thoughts into it.
It's hard to draw a line.