The odd thing about the announcement of Gilbert Arenas' season-ending suspension was the claim that he asked for it. Literally. Why would someone want to be suspended for a whole year? Obviously, he gets more money that way.
According to reports, Arenas told David Stern during their meeting on Wednesday that he expected a season-long suspension, that he would accept it, and that he would instruct the player's association not to fight it. That's awfully generous, isn't it? Doesn't he care that he won't get to play again until next fall? Maybe? But he cares more about the four years left on his $111 million contract.
The Wizards would probably very much like to void the remainder of that contract under the ambiguous morals clause that players must abide by even though no can agree on what it means. However, the player's union is prepared to argue that the league and a team cannot punish a player twice for the same offense. The NBA agreed to suspend him without pay for one specific crime and his lawyers would argue that Stern's decision is more then enough. By accepting the harshest punishment short of out right banishment, the Wizard's hands would be tied.
Also, as the New York Times points out, allowing the Wizards to void the contract of Arenas would actually make it harder for the NBA to get new "morals" language written into the next Collective Bargaining Agreement. If it ain't broke, they can't fix it.
That doesn't mean the team won't try, of course, especially if Arenas ends up in jail and in any scenario it will almost certainly go to arbitration. Had Gilbert fought the suspension (or worse, won an appeal) that would only undermine the case that he's suffered enough. He may hate the Wizards and he may hate not playing, but he would hate losing that $80 million most of all. The man is insane, not stupid.