I suspect that might be at least partially because, in some cases or for some people, getting out of a deep depression might involve kind of disowning or denyin

I suspect that might be at least partially because, in some cases or for some people, getting out of a deep depression might involve kind of disowning or denying the kinds of emotional states and thinking that were part of the depression. If the depression was hard enough, it could be that one doesn't want to feel them again, and genuinely understanding a feeling requires feeling it at least in some way. This is just a hunch, based on personal observations, not any kind of psychological theory.