That's not it! blaming the hunter was incorrect when the project failed. But i think the problem will be with the BM and project team because BM is the person who will be responsible for the process of bringing the project to the hunter, if the project is a scam then part of the responsibility.
The campaign manager does not responsible if the project fails or becomes a scam project on the other days, the manager only takes responsibility for the campaign that he managed not the project unless he is a part of the teams or involved in the development of the project.
The campaign manager is not responsible for whatever the negative things happen during bounty, he is also getting paid for managing the campaign. Even he is also one of the people like us, which he will research the basic things about the project and start promoting the campaign to get awareness about the project.
But in some of the cases, I think bounty hunters should be able to know the things clearly before providing their service to their clients and some of the clients do not seem good still they give thumbs up to the project just because they get money for their services. So if those managers could stop this by not providing services for the people who seem suspicious regarding the project.