You can get behind that? Good for you, except you're forgetting the fact that they consider every wastelander a "filthy mutant" so there literally is no reason for anyone to join them. You brought up the Empire, but the Empire didn't have a genocidal policy against aliens/mutants/whatever, all they really care about is complete control over the galaxy. Someone with the right motivations could join their cause, be it for personal gain or desire to live in a system like that. However, if you aren't part of the Enclave, there's no way in hell you're joining because you are the very thing they oppose. The only scenario I can see is them letting you think you're joining, getting you to do their dirty work before shooting you in the head and dumping you in the pile of "mutants" you just helped kill.