I just watched a bit of a Trump speech and was struck how it's pretty much standup comedy without the jokes.
You could do what he does with a comedian like Louis CK or Sarah Silverman doing a standup routine, only say nasty things about different nationalities and religions. That's Trump. Pretty simple formula.
I think basically Trump supporters are saying they want Presidential politics to hold their interest. That's something comedians are very good at.
I'm sure there was some of that with Obama.
Alternate theory: It's the obnoxiousness, dummy.