Han is only using that as an excuse because he feels he doesn’t belong in this war. This is his way out of the Rebellion that allows him to keep honor. The Rebel officer is just being comprehensive with him. This is a dialogue where what is actually said is not relevant*, only what is unsaid has a meaning, and the 3 characters (Han, Leia, Rebel officer) all understand that. So there is nothing wrong in this dialogue.

not relevant for the scene itself (Jabba and stuff), but within the movie it is later used to stage the third act as well as the events of the following movie, because Kasdan et al. were fucking brillant (I still don’t get how he’s failed so much the script for Ep VII. This really is a mistery to me).