It's true you mainly use your feet when playing soccer, so on the face of it, "football" seems like a much better name for the game. Especially when β outside of the lonely kicker and punter β players don't use their feet much in American football (except, you know, to move).
But!
Before you anti-soccerites get too smug, did you know that a number of other countries besides the United States call it "soccer," like Australia, South Africa, the Philippines, and Canada (to name just a few)? Also, did you know that the word "soccer" is of British origin, and was used by 19th century Brits as a nickname for what they now call football? So don't make fun of the word "soccer" too much, British people...you made it!
VERDICT: Point to the "football"-using part of the world. While the history lesson above may have won the ol' US of A some points, in the end, it makes more sense for the game where you kick the ball to be called football.