From what I have gathered, there was a group that was blatantly advertising paid content on the chapters, got caught redhanded, and blocked. They then went to mangadex discord support channel and asked why they got blocked, and they were given the clause, to which they replied ”many other groups do this, why only us?”, and a mod asked which groups had done the same thing, and you know the rest of the story.
caught this by pure chance, but this is essentially unreported behavior made aware by a third party that was doing the same, it was simply put a matter of time.
That being said, I don’t remember asmodeus advertising they had paid chapters, only that they had more chapters released early on their site (a chunk of which did not have a buffer of chapters between the free and paid ones). Not sure but to me it always felt kinda scummy, but I simply waited for months or for a snipe to make them release a good chunk here.
Anyway, it’s very likely no one reported them explicitly, so the mods were likely not fully aware.