They may be gross, but so is having rotten corpses sitting in the open. By getting rid of those corpses they are doing us a solid, so turkey vultures are cool in my book. The only animal that's profoundly not cool is mosquitos, they're a worthless species.
Microorganisms disintegrate the corpse into foul-smelling goop that is highly infectious and stains anything it touches. I'll take the vulture over that.
It's a great strategy when you can't sweat. Animals roll in mud to keep the sun off and for evaporative cooling. I forget, but I'm pretty sure kangaroos rub their spit into their fur for the same effect.