Bunch of millionaires rolling around once they get bumped, acting like they broke their leg in half.

Prevents referee from ignoring fouls and thus prevents dirty aggressive play. Does it matter to you that the actors in your favorite movie earn a lot? Or do you bitch about that too? Those sportsmen are essentially entertainers.

[...] and puts up ads on every flat surface in the world.

Well, that's how the football industry increases the demand of their entertainment. Byproduct is that it makes the sport popular, and sport is healthy, so it's good that it becomes popular.