Why do the French play rugby instead of gridiron, American football?

Doesn't that prove that they're not real men? I hear that rugby is the second most popular sport in France, therefore, it must be a sissy sport. Why can't they be real men and put on some helmets, put on some shoulder pads and go out and play gridiron instead of some wimpy game with a bunch of boys wearing shorts and collared shirts and one another?