It is disgusting and that's on the owner. Foxboro used to be as bad as that...that was until the Kraft's came in and cleaned things up. They have cam's pointed at the stands, and workers who face the stands and watch for shit like this. You throw anything or start a fight, you get ejected and lose your season tickets if you have em. They don't need to hold on to fans...the waiting list for season tix is 10+ years long.
Another remedy is to raise ticket prices, so uneducated scumbags can't afford to go