Incidentally, I was surprised when he said to himself in the mausoleum that he must help poor, deluded Carl. It gave the impression that, contrary to what we have learned about Trask so far, there is some Christian charity in him.
Gregory believes with all his heart and soul that he is the most righteous and compassionate of human beings. This isn't just some simple conscious lie that he uses to score big bucks for himself. It's an
unconscious lie, and those are more dangerous. He is compelled to act in a manner which appears good and kind, as he sees it (and he doesn't see bellowing accusations at people to be unkind, it's the old cruel-to-be-kind thing). He hates the Collinses, and shows it to them every day without showing it to himself. You can tell yourself you are compassionate toward those you hate the most, and that every act of hatred is for their own good. My father was this way.
Trask really believes he can't leave the animals to run the zoo. In no way does this constitute "good intentions" and in no way does this absolve him. Liars just lie tpo others, but hypocrites also lie to themselves, and they believe their own lies about themselves far more than others believe them. They lie to themselves to give them an easy, irresponsible way out of all moral dilemmas. It's not conscious self-deception (that's contradictory), but it is
intentional... on a somewhat lower level than consciousness.
Listen to him still defending himself, calling himself a savior of souls, when it's juszt him and Evan in the room, and he's just carried out a murder with Evan. He wouldn't think Evan could be fooled by this. He can only be saying it because he believes it. He also thinks he's on this Earth to save people like Carl... and if he can get the family's money, what better reward for his spiritual services? That's the kind of thing that's bouncing around in Trask's head all the time.