I think GP's point is that "just do it" shows a lack of understanding that an inability to "just do X" is often a symptom of depression that leads to people not talking about it, because people who haven't experienced it think you must be lying about having decided to do something and not actually then doing it.

Consider: there was a study about a guy who was paralyzed from the waist down, who got an implant to bypass the injury, and with a year+ of walking with the implant, could eventually walk to a limited extent without the implant.[1]

This suggests walking can be used to treat loss of ability to walk. Unfortunately, there's a catch-22 there...

...and so too with inability to make yourself do anything.

[1] - https://www.nature.com/articles/s41586-023-06094-5

> Well yeah, but you gotta start somewhere

Wait, I thought those things solved depression? Why are you hedging now? Did your initial analysis suck, and you're just now realizing it? Are you figuring out that maybe this is slightly more complex than "just be happy" and that maybe you're not the only person on the planet who's ever thought about this?