Even if this were true, it doesn't address the other element of the problem, which is that flooding the zone with horrible crap makes it harder to find the good stuff, and forces you to waste a lot more of your own time filtering crap.

Yes, I can usually identify AI slop within a couple paragraphs, but it still wastes my time to encounter it, and if it's my entire feed, it's going to drown out the good stuff I'd actually want to read. Same for literature at a larger scale, to say nothing of the countless scandals where obvious AI-written crap wins various writing competitions.