sirvoddmort, I respectfully have to disagree with you.
Football is football. Soccer is soccer. There is no term “American soccer” versus soccer.
The term football belongs to the NFL. Period.
Now, the logic that 10kg of equipment equals and short bursts of play does not equal a sport, is clearly a flawed syllogism.
While I understand people speak about sports in terms of emotion, football indeed requires great training, skill, and talent on behalf of each athlete and their respective jobs. And this includes speed; great speed, which you identify as a negative.
Further, the strategies played out by team members in each individual position to work to an overall objective (play) and win, or lose and try to come back and win, is indeed a sport of all sports; which can only be played by those talented and conditioned to do so.
In a way, football is like chess where all the pieces move at once simultaneous to the opposition also moving at the same time to defend against the offense.
It is a great sport!