Have you ever calmed yourself down when you've been upset? Or recognize that you're getting emotional and take extra care when you choose your next words? That's the type of thing I believe your parent is getting at. This is some of the motivation behind techniques like CBT. It's not implying that people choose to feel depressed, but that one can have some control over how one is feeling when in the throes of otherwise overpowering emotion.

I would describe those as coping strategies to avoid maladaptive behavior, not changing the underlying emotional state. I find it hard to see how "actually choose how to feel" can mean anything but the latter.

Then I believe, given the greater context, that you're choosing to read it uncharitably. If your point is to search for greater clarification and mutual understanding, as opposed to argument, I think you can likely do better than your current approach.

> If your point is to search for greater clarification and mutual understanding, as opposed to argument

I don't believe those things are actually opposed in any meaningful way. Also, I think it's possible to take the principle of charity too far. At some point, it's just as much putting words in people's mouths as a knee-jerk misinterpretation.

I'm saying that people capable of coherent thought can choose, over time, not to have mood disorders, which is a subtly different point.

I fully recognize that when you're in a depressive state, things seem hopeless and that you feel unable to choose a different state.

My proposition is that in all but the most serious cases, you actually can choose, if you're given the right mental frameworks and sensory inputs.

Of course, the devil is in the details of identifying and providing those frameworks and inputs.