Relatively few of a Paladin's Class Feats are actually contingent on keeping to the Code, and there are very few levels where a Feat that would be lost if the Paladin falls is oyour only option (and those are easily covered with Multiclassing feats). So you can play a Paladin of any alignment who completely ignores the Code, and you'll give up Lay on Hands and a magic mount/shield/weapon, but you'll still be able to have Divine Grace add to your saving throws, gan angelic wings at high level, have various bolstering divine auras, and sense the presence of Evil. Even the feats that add an extra tenet to the Code remain useful, since their mechanical effect (with the exception of the Oath of Vengeace) is to increase the usefulness of Retributive Strike against a certain class of enemy.
On the whole, I think this is a feature rather than a bug, but there it is.