I trusted the Bitcointalk bounty program, but I saw many fraudulent ICOs even in the btt.
Do you think you should continue to use threads that encourage such fraud?
That's because they aren't moderated, and likely will never be. This place is ran in such a way that the community takes care of community issues, while moderators and admins only address forum-specific issues. This is good in my opinion, because it decentralizes influence between users and moderators. The community basically decides which way it's going, and there's no gatekeeping.
It's all up to the people involved to practice due diligence on whatever they may want to involve themselves in.