I think it's more likely that their flagging is heuristic based and could easily defeated by a malicious extension author and giving detailed feedback makes reverse engineering the rules trivial.
Telling people that they are going to be severely punished within days by a very powerful global entity, without telling them which specific rules they are in breach of or what they have to change is a dystopian nightmare.
Well, if the reason is the "https://*/*" permission or something like that, and it is flagged and reported automatically, and everyone learns not to use it, it's a win-win. Benign extensions will have smaller targets on their backs, and malicious extensions will become less malicious OR will have to jump through hoops to achieve what they're trying to achieve (and will become easier to detect).