Because American Football is way more fun to watch than watching a bunch of guys kick around a ball without much scoring.
Maybe you should give Australian Rules Football a watch. A reasonably high scoring game where there is a lot of handballing and kicking done. Look up Essendon Bombers, they are the ones I go for.
I'm sure I'd find that more fun to watch than soccer.
Soccer is almost as boring to watch as golf and Formula 1.