I’m trying to pick ones with meaningfully different aims so that I can try to keep some sort of separation in my head. Otherwise I’d quickly lose track of what conversation having where, with whom and why.

This is the appropriate time and place to discuss the codebase and project management approach of the Lemmy FOSS project. If you don’t like hearing people you disagree with talk about those things, you should be going to do something else rather than rudely trying to make them shut up. Even from the perspective that you just want to challenge this user about the appropriateness of how they are expressing their opinions and frustrations, you are going too far and behaving inappropriately yourself with all the personal attacks. Just leave it alone and if they are saying things that you feel need to be addressed just report and move on.

If it helps clarify things for you, the person you are arguing with doesn’t understand what you are trying to say with regards to how autism informs your interactions with others online and is arguing against a point you aren’t trying to make. They are however entirely too dug into arguing against that point to easily and effectively get them to understand what you are actually saying and respond to that without the baggage of already deciding that they entirely disagree with you to the point they think they are entitled to be rude to you because you don’t agree with them.

The conversation you are in in this thread is more difficult than it ought to be and while some element of that may be due to your autism, there’s also a lot of failures from the other side of it making the conversation harder than it should be. At this point you are not being treated kindly and respectfully by the other person (because they are frustrated and handling it poorly.) Better to just disengage with them and shrug it off as a misunderstanding and bad behaviour not of your making as best as you are able to do so.