Not racist. More as inaccurate as comparing marching music to free jazz. It's both music, but one evolved from the same base to a higher level.
In American Football, the layers have rather limited possibilities, in my opinion, as the whole game is rather one that is played proxy, in realtime by the coaches.
In "World Football" (aka. Soccer), the coaches train their teams and players individually, but on the field, the action is on for 2 x 45 minutes, no breaks at every couple seconds. The players have way mnore possibilities and liberties, and that is what seperates the games.
For further information as origin, separation into different kinds of sport etc, the Wikipedia Page is pretty good:
http://en.wikipedia.org/wiki/Association_football