I see your point, and this may seem really nitpick-y, but I think I would argue that Kaladin had less apathy--the inability to feel--and more anhedonia--the inability to feel pleasure. I say this because even when he was in the caravan with Tvlakv and all the way up until the night at the Honor chasm, he felt things; he felt guilt, anger, worthlessness, despair, etc. I would say that he definitely tried to be apathetic but he just couldn't, which is part of why he made the decisions he did to save the bridgemen.