Most of the bounty managers are quite fair, you probably have found a nasty one. I recommend that you particularly play only with the established ones if you have these feelings.
Yes, in my opinion, not all bounty managers are greedy, only some people commit fraud to enrich themselves. So it is true that to participate in the bounty campaign we must choose a manager verified by this bitcointalk forum.
no manager verified by the forum, the moderator gave red trust to anyone who committed fraud including the manager.
many trusted managers, for example sylon and amazix they are the best managers in this forum.