Ok I'll bite. Why not?
simple... it's horribly placed.
Its only in the american release, It's not in ANY of the promo's for the movie, and it seems like they were trying to say that spiderman was the symbol of being an american (when that honor goes to captain america or superman)
Huh? I thought Superman was Canadian and Jewish.
The creators were.... Superman himself is now as a icon, connected with america. "Truth, Justice, and the american way" ring a bell?
if you really wanted to get technical he's not human.