mmmh... some people here seem to say
football = USA
soccer = Europe
but the truth is more like
football = USA
soccer = Europe, Africa, Asia, South and Central America, Antartic (yup)
Actually, I this was not an american website, I would not even use the word "soccer" as everywhere else in the world we call it "football" and we call your football "american football" (you follow ?)
Beside that, I think the arguments of low score and difficulty to put commercials are quite good. The cultural difference too : I think american people usually don't like it when they are not the ones who spread their own culture around the world so they don't easily accept what's coming from other countries (metric system, movies, food and, here we come, soccer)