Your friend is more or less right.

Your snake doesn't think to himself "Hey, I bit at the guy and he put me back in my home, so if I do that, he'll leave me alone." But it IS operant conditioning, that if he strikes, he ends up back where he is comfy, so he will learn to strike when he's nervous, because he ends up in the non-nervous-making place(i.e. his tank).

Make sure that when you are handling, that you are supporting his weight, not dangling him by one spot on his body. No quick movements, and if he acts stressed, you can calmly return him to the enclosure, just not right after he's struck. When he's been handled enough times, normally a snake will realize that nothing bad happens when he's being held, so they calm down about it. Some snakes do stay very nervous, but it's rare, so there's a good chance that he'll settle down.

Babies are way worse about being keyed up over things than older snakes. The smaller the snake, the more creatures can/will eat them, so it makes sense for the survival of the species for babies to be overly paranoid about larger creatures wanting to eat them. Be patient and I'm sure he'll come around.