I don't like it any more than you do, but the people who don't pay attention to politics but vote anyway are the ones you have to attract in November. They determine the outcome of the election.
Guiliani might lose the support of the one-issue conservatives, although I think many of those might still support him if the alternative is President Hillary. They wouldn't like it, but the alternative is just too scary.
But Guiliani connects with the David Letterman audience, and that's not something to be dismissed as politically irrelevant.
You are one mean arsehole. I bet I know why you like guns so much, its a compensation thing.