One of the requirements of the GPL is that credit is given (and indeed this is needed for enforcement to work because the GPL leverages copyright).

The project could, yes. It wouldn't necessarily change the legality of using it in non-GPL projects, though. If people were only using it in license-compatible projects and it was license-compatible with GPL, I doubt anyone would have any complaints (even though in theory it could also be picking up stuff from other incompatible licenses).