From my understanding, all the locals where this happened think this dude is a colossal dumbass.

I think his legacy is slowly changing though, and people are less impressed by his antics today than when it happened.

He wasn’t a dumbass, he was just suicidal.
He first left his privileged life, then his family and friends, then society.
If he actually wanted to keep living, he could have left the bus and simply walked back, 3 days before his provisions ran out (it takes 6 hours to get to the trailhead).
But he stayed, even though he didn’t have the skills to live off the land. He accepted death, until it came close, then he regretted his decision and tried to get out.

To me, this is the simplest and most plausible explanation.

Somewhat related but it’s odd to me how many people I’ve met that feel so strongly negatively about him. Maybe as a herd instinct to warn others?

He wasn’t exceptionally selfish as he had no serious responsibilities.

Not sure the hate is directed at him, but at people glorifying him

Yeah, I haven’t read his book and have no strong opinions on him one way or another, but when the book came out, I remember him being presented to us as if he were some sort of spiritual or philosophical luminary to emulate, and it’s always rubbed me the wrong way.