WALL-E Duty Quotes

When EVE returns with the plant, the Captain waters it, and he talks to it. He seems to apply this same sense of duty to Earth itself, like he needs to go look after it (conveniently forgetting that humans screwed everything up in the first place!)

AUTO is just following orders that were programmed into him. Does that mean he's evil, or just (unlike everyone else in this film) just following his job description?

Here's a little robot conundrum. It seems that AUTO both has to follow his programming directive and orders from the Captain. Why doesn't the Captain just order AUTO to send them back to Earth?