I don't understand his problem?

I chose relationships because that seemed closest... really i dont have any relation to this guy. we know each other because we're part of the same online gaming community. the most interaction I've had is forum posts and the occasional group game. Somehow I've done enough to make him dislike me, which I didn't figure out til a few weeks ago. before that i thought we got along just fine. he's a nice guy, or so he seemed, and gets along with everyone. i felt like we could be friends. I found out he didnt like me when I made a joke that upset him - completely my fault and I apologized for it, but suddenly all the truth came out. He started talking about other times I "insulted" him, which I was not aware of. I told him I was sorry again and explained what I meant and he kinda backed off, but then he came back and started pulling up past posts. these had nothing to do with him but he used them to try and show me how "negative" and "resentful" i was. all these sweeping accusations that are completely untrue,completely misinterpreting and taking my words out of context. I told him this too and he backed down again. I told him to leave me alone and he did. he even said maybe he misjudged me, to his credit. but his judgements were honestly SO OFF. he was accusing me of things so bizarre i dont even know where he came up with them. it had me questioning myself for a day or two, but now I'm just confused, and wonder if maybe he needs help? where did these huge accusations come from?

Hi, I don’t really know much about online gaming at all, but is there a way you can shut down communication with him? Like said above, he doesn’t sound stable, and you were right to tell him to leave you alone. Yes, he backed off each time you apologised or explained things to him, but he still came back and tried to make you look bad. He even had to drag up old conversations, seriously? You don’t have to keep apologising or explaining yourself to him.

I can understand him getting offended if you really did insult him and he had a right to bring up other instances of when he felt insulted, but he didn't say anything earlier and is just now bringing it up along with trying to twist other conversations into making you look like the bad guy and that is definitely a red flag. I've had experience with a guy like this that tried to always make me look like I was the bad guy and honestly, regardless of how many times you apologize, he might not be satisfied and he might continue to bring it up over and over again like he already has. In his mind he is the victim and you are the bad guy. It's basically a power play in which you'll always be stuck apologizing for everything and actually believing you did something wrong. Since you aren't close or have any relationship outside of gaming I'd definitely just cut him out. You two aren't even close and he already has you second guessing yourself.