Yeah sorry but I'm going to have to say that the guys who are way better athletes, most of which are having car crash level impact into each other multiple times per game and every practice are playing the harder sport.
It's a pointless argument. You like soccer, you're clearly European or Asian, or something. You probably don't follow basketball or football (NFL) at all and know nothing of the sport. I've watched a significant amount of soccer and played it, the athletes aren't better than the NBA or NFL, not even fucking close.
It's a skilled sport and it's the "biggest" sport in the world, sure. I would argue that the talent pool and athletes are not comparable to NBA/NFL even MLB, despite that.
Soccer is a game of skill, there's offsides so speed isn't a massive factor. Strength and power isn't a big factor. Size and strength isn't a factor. It's barely contact, people flop everywhere. It's a skill sport. I'm not saying it's a shit sport at all, but claiming it's the toughest sport in the world is retarded when there's NFL football, MMA/Boxing, NHL even, those sports require way more toughness. If you meant toughest to excel at? Again all the top tier athletes in the US are playing basketball and football and baseball, and even NHL/Boxing/MMA, they don't play soccer.
And yes the US has the best athletes in the world by far.