Not that I agree with you at all but let's just assume for the sake of argument that you are. If that's the case there should have been a discussion between the den leader and the parent about what they have an issue with and see if they can work out a compromise. Not expelling a kid for a made-up reason and for what even you admit is not his fault. That is simply a cowardly thing to do that in no way shows the kind of leadership that scouting is supposed to be teaching.