The thing is, people who post trash likes posting on trash topics. It's pretty much the best place for them to spam some replies(with the same level of trash quality) to get the required postcount for their bounties. That's why you see those trash posts having so much replies in less than an hour, compared to topics that are quite complicated for them(e.g. topics about BIP39 wallets, etc)
That is true, they use those topics to increase their number of posts for their bounty programs, so trashy posts go updated again. Those topics or questions usually just need a common sense to answer. Separating the newbies of course, but they should learn that before posting a new topic, they should have read first the rules and regulations in the forum.