Because, if it weren't for "their players" wearing that clothing in public and on the way to and from appearences, they wouldn't have nearly the support, money, or interest that they do in the league.

I'm really trying to say this without sounding rude b/c I'm not trying to be rude at all, but if you don't live in the U.S. then you really can't argue this. At least not the marketing part, b/c you don't know how it is.

__________________