They should've banned free adult sites first. How is free sports worse/more "dangerous" than free adult sites? 
I'm not sure how either is dangerous.
One is violating copyrights, the other isn't.
Though I love the illegal sports streaming sites, I can't complain about blocking illegal streams. Still, I look forward to people finding ways around restrictions to force sports league to have better pay online options. I would gladly pay for an option to see all 82 Celtics games and then all playoff games online since I will soon dump my cable.