Well, this isn’t usual. This is actually really rare. Almost all of the interactions I have with users of my libraries are great. People are generally appreciative and kind, or at least not rude. This is an outlier, and I try not to let these things sour my experience.
He’s frustrated and he’s being abrasive because of that, but that doesn’t make him a bad person. I try to respond without being rude back, but just stern. Usually when you do that, people will either not respond again or apologize. I’ve never had a user keep being rude, and if I did, I would just ban them.
Sometimes people just kinda forget that on the internet they’re still talking to other real people, you know?