that's not true at all. the hitting techniques are entirely different. in rugby, you have to be incredibly fundamentally sound. in football, you can essentially just launch yourself at people with zero regard for personal well-being, which results in the devastating hits that we see. in football, you have quarterbacks getting blindsided, receivers getting blasted in mid air, and defenses players getting absolutely smashed. Rugby is brutal, no doubt about it, the risk of injury is so much higher, but to say that american football players are pussies is just silly. The style of play in both sports is entirely different, which leads to completely different styles of hitting.
look at this, greg jennings scores a touchdown with a broken leg. pussy? i think not.