I don't think Locke is someone who has bad intentions. He helped Charlie with his drug addiction problem and he seems to care about the other people on the island.

Let's face it, most of them have lied at one point or another. Locke may think that he's no longer looked upon as one of the leaders. Kate and Sayid are taking charge and most of the other people aren't as dependent on him as they used to be. The less time that he spends taking care of them the more time he spends on his fairytale theories.