It's rarely that simple, and I'm not sure what Wikipedia article you're reading. Impressment - kidnapping of American sailors into British naval service - was a pretty big issue. http://en.wikipedia.org/wiki/Origins_of_the_War_of_1812
I didn't mean to comment on whether the war was justified or not, but simply that it was USA that attacked (and so the war doesn't quite qualify as an attack against America).
