Oh, I don't doubt some people will inform themselves and some people will make some good decisions as a result. Just unconvinced that it'll be a net improvement in the state of public knowledge

Why? Uninformed might have different but still wrong idea, but some people will learn.

I don't think you could get net negative in this situation.

Or am I missing something?

If significant numbers of people become deeply committed to beliefs which are clearly incorrect to rationalise being duped into losing money on a meme, I'd argue that was pretty negative.

This happens in ponzi schemes too, people will find a scapegoat rather than feel their ignorance or greed was the problem. Here it's Robinhood and hedge fund conspiracies and Wall street playing by different rules. When MMM ponzi scheme (https://en.wikipedia.org/wiki/MMM_Global) peaked everyone was furious about people writing negative editorials and government warnings not to jump in.

I nearly put a reference to MMM true believers actually voting Mavrodi into Parliament to give him immunity from prosecution for defrauding them in my original post. Wonder if any hedge fundies shilling GME on WSB whilst betting big in the opposite direction are bold enough to try that if the SEC comes after them...

How much can they have really learned in a few days? Certainly not enough to be "trading".