Just seen the video of the monkey chanting at the Serbia v England U21 game (Stadion Mladost) which saw Danny Rose sent off for kicking the ball into the crowd after the final whistle. This should be easy. Ban them from playing international football as punishment. Throw the book at them faster than they threw missiles and coins and seats. How else can you truly make an example out of these animals?
Oh no, wait, I've got a better idea. Fine them 10k instead, that should cover the 'fervent' support. Slapped wrist will do the trick.
Punches and head-butts from the Serbian players too. That'll bury the racism deep enough to be brushed aside. Again.