mutated humans, they're not really seen as human beings, not fully anyways.
Fun Fact: Anyone born in the Wasteland has 'mutated' DNA, so Ghouls are just folks who have taken in a more than others.
Strangely, I've always wanted to do this too. Probably because of Mad Max, but it other than that it always seemed like it would be a really interesting playthrough (in New Vegas it would have been really fun).
Yeah, I got the idea in Fallout 3, before the Police Hat was made wearable in DLC, I thought 'if there was a way to wear a police uniform, that'd be SO awesome!
' Sadly that hope was never realised.