I appreciate what you are saying.
For the smooth running of the forum, it would have been better to ban the user, but that seemed like a drastic step to take. I advised them to step back the posts a bit and do more reading and less posting of "hobby horse" ideas. Then they posted in this topic with "That’s the most ridiculously absurd idea I’ve ever heard in my entire life" which was the opposite of what I had advised.
You certainly don't need to be an expert to participate in the forum. Its hard however to have a meaningful discussion when there is a lack of understanding of basic physical principles, and this, combined with an inability to take on board contradictory opinions, make it hard to continue.
Which is the point I'm trying to make.
I don't think you talk to a 4 year old as you talk to a 19 year old. And you don't talk to a 40 year old as you do with an 80 year old.
You don't explain things in the same way to a baker as you would to an engineer.
Expecting him to change his behavior after telling him off as you would with any other user, and continuing the discussion to convince him of how ill-advised his ideas are, is not a very realistic prospect.
However,
dura lex sed lex and I'm not arguing to treat him in a different way than any other user. As I stated before "If his posts are unrelated to the threads he has been posting in, or violate the forum rules in any other way, it would be better to just ignore them or remove them".
Removing his posting privileges for a time could also be an option, if it's too tasking for moderators to check the posts he makes. And in case he kept ignoring the previously issued warnings, banning him could be the right course of action, since it's clearly stated in the rules that "Membership of this forum is a privilege not a right".
Anyway, I feel some people could have refrained from clicking the "post reply" button to avoid a meaningless display of one-upping him and demonstrate how foolish his ideas are.
And it seems to me that some people even felt more emboldened in taking part into this activity after seeing your reply.
Looking at the snarky remarks he received, here and in other threads where he recently posted, I don't think those actions fall exactly in line with the Golden Rule of "Treat others as you would have them treat you" either, and this even before taking into consideration the fact that he's autistic.
Do we want every discussion on the forum to center on lava-proof landing gear, because of one user's pet idea?
To be fair, I think I've seen worse ideas here in the Alternative History and Future Speculation section, by people that are probably not autistic.
I don't think they have received the same amount of flak, though.