Why do americans use confusing terms?

Rugby is football, it is Rugby to us. When we say football, we are reffering to American Football. When we talk about the football the world plays (but not so much in the states) we call it soccer. That is to avoid confusion. American football involves punting, fieldgoal kicking, and kickoff's, there is lot's of kicking involved. Nobody in america plays rugby and only girls and s play soccer.