Why? Because alot of the pirates were the cheaters/hackers. It didn't matter if they got banned coz they can make a new fake serial and a new account easily, so getting banned is not a problem.
BUT NOW, Crytek has FINALLY cracked down on the pirates and now pirates cant play online with fake keys, which means no more cheating/hacking pirates.
The only cheaters now are the legit owners of the game...which means that all Crytek needs to do is FURTHER Improve their anti-cheat security.
But really, its only gonna get better from here.