As someone else pointed out, there is no one sport that has a monopoly on the term "football". Also, complaining about Americans who refer to American football

As someone else pointed out, there is no one sport that has a monopoly on the term "football". Also, complaining about Americans who refer to American football as "football" often sounds like thinly veiled xenophobia disguised as pedantry, a la "here's one more thing I hate about those stupid Americans..." It's such an odd thing to complain about that it comes across as the tip of a hate iceberg rather than an actual complaint about terminology.