> even if you do send an email and the mods eventually read it and take action, by the time that happens, it's likely that bunch of users will have already wasted their time unknowingly

That’s certainly a consequence of how the site operators choose to accept user reports to by mods, yes, but it’s sometimes treated as an excuse not to write the emails to the mods. They can flag off the thread, autocollapse it so it doesn’t take up discussion space for future readers (such as those at work offline for a 3-day IT shift in a secure bunker or whatever), et cetera.

> commenting something like "this is a bot account" is done primarily to inform other users that might not notice

It’s a nice sentiment, but that’s also expressly forbidden by the guidelines/faq (“Please don't post insinuations”, which I’ll suggest to them should be extended to include AI something or other), and I tend to report those accusations as the ‘opening’ guidelines violation so that mods can step in before mobthink kicks in and make their own mod judgment about the matter. A repeated pattern of accusations of guidelines violations in comments is eventually going to attract mod censure, and so I advise against it, no matter how kindly the intent.

> it's finally time to consider some sort of on-site report system

I do agree that it’s clumsy and I make a point of saying that to them about every year or so. Perhaps your email to them about it will be the one that persuades them! I remain ever optimistic.