From my own experience, there is significant overlap between burnout and depression. The root causes are different, but the symptoms are the same. The echos I hear are based on having experienced both.
If you have never experienced either, it's hard to understand how completely they alter personality and decision making. Seemingly mundane problems become insurmountable. Trivial items become weirdly important, and critical items become... not quite ignorable, but hard to prioritize.
It's very hard to behave reasonably when you feel like you're lost and drowning. Instead of making simple and obvious decisions, I found myself making completely irrational decisions. Looking back a couple decades later, some of my decisions were bafflingly silly. Others were tragic. In all cases, my decisions were based on overwhelming emotion not logic, experience, or my personal priorities.
Perhaps you've gone two or three days without sleeping, and noticed yourself behaving like you were drunk but tired. Now take away the loss of coordination, increase the loss of executive control, and let it sneak up on you over months or years. That's the best I can describe the experience to anyone that hasn't had it themselves.
I found the author's essay beautiful, cathartic, and helpful. It helped me to empathize with what he'd experienced, and reminded me how complex we each are as human beings. It gave me new things to think about as I consider my own career path and life. And it was interesting seeing the last two years of COVID from a European's perspective compared to my midwestern American perspective.
In other words, from my perspective the essay was an example of humility and generosity, and I'm grateful for it. If we were all so willing to examine and share our inner experiences, perhaps the world would be a slightly easier place to live.