Because he bit someone during a game of football: its exclusively his own fault and if Liverpool want someone to blame, they should blame him and not FIFA for the punishment that he gets. Using that logic: banning any player for any offence ever is "unfair" to someone! It isn't unprecedented; Cantona was (rightfully) banned for attacking a fan shouting abuse at him: and that affected both United and France. Was that "unfair" to the French national team?
Rumours are that Liverpool are considering his future as well: since the Ajax biting incident he's been banned for 36 League games and 9 internationals; and that's before this ban. That's without receiving any red cards as well! He's a good enough player but his attitude stinks and Liverpool are paying a fortune for a player that has been banned for pretty much a full season worth of games in four years: for such fine things as racism and biting. All of my Liverpool fan friends are saying that the club really should think of finding someone who may not be as good: but might actually treat themselves, their competitors and football with the respect that it deserves.