There are some excellent answers here, but to add to them:
Evil can be a team player.
One of the most likeable characters I've played in games was a Chaotic Evil kobold who was utterly without human morality, but utterly cowardly. His party is his clan, and he follows their lead. They are his friends, whom he protects and depends on. He'd back them in bloody conquest or lofty heroics. He'd shrug his shoulders at things they considered dirty work, and happily take care of problems for the party behind the scenes.
A player who routinely does things that make the party uncomfortable, contradicts party goals, and generally makes the game less fun for people around them isn't looking to play an evil character IMO. They are looking for an excuse to troll, and they could just as easily do that with a character of any alignment.
