I'll be honest, it kind of sounds like you are using these guys.

Hopefully thats not the case and these guys get something in return for helping you promote these bands.
I'm a bit confused now as to what you are actually asking. You said you didn't have any problem "knocking down a guys manhood" but you feel bad because they all have a depressing story. If this is the case I don't think you really need to make them feel bad about themselves, but rather just make sure they understand that the relationship you have with them isn't personal, its just business. Also bear in mind that when you establish these relationships you don't lead them on, or flirt with them in a way that makes them think otherwise.
I think it goes without saying that if a guy has interest in you he will go out of his way to help you (promote your band, etc.) Just make sure you aren't taking advantage of this.