I do not think that bounty manager ignore the bounty hunters. The bounty managers want to pay all the bounty hunters on time and also wish the project to succeed but all the delay in token distribution is from the Project team. In most cases, bounty managers have no control over the project as they are only doing the job as bounty manager.
Indeed its not the manager's fault why there's a delayed on distribution or if the project turn out to be a shit project or a scam.
Because the bounty manager is also doing his part to manage the bounty and should not be held liable for any problem when it comes to payment and the progress of the project.
The dev is the one responsible. Thats why we need to be more wise when choosing where to participate because many projects are really not worth for our time and effort.