They don't. The MLS had a 20,000 average attendance last year. That's brought more people to the stadiums than in Eredivise and even the Argentine league, both being very traditional footballing countries.
These are just stupid people, they're everywhere. See, the thing is, If Europe was a single country as big as this one you'd have just as many stupid people. Actually You have them but at least they're split over dozens of different countries living in different cultures.