I'd like to thank the gp for his comment and his honesty; I think his participation adds a lot to this discussion.
That said, I felt just as uneasy as you.
Here's my experience from the Funemployment thread, if anyone's interested -- not FU money, but a life that feels just as free: https://news.ycombinator.com/item?id=7932707 (I thought about commenting on this thread, but I already commented on the 'Funemployment' thread).
I think that "emotional immaturity" is a cop-out, though, one that I've seen a lot. What's mature?
I've seen, known and met dozens (hundreds?) of expats, and I fear that the real reasons might be a bit more grim: I don't think people really know what they would run away to do.
It's easy to funnel people towards technology and startups if they want to get rich. It's 'easy' in the sense that, whatever the reasons you might want to get rich, technology can probably help.
But on the opposite end?
Where do people go once they've achieved functional independence (through retirement or other means) and can basically take work or leave it?
Well ... that's pretty personal. It fans out, sometimes to really weird and specific places.
In this case, the gp has found one really good friend, who 'gets' him. The two of them have a bromance going, and they have a hobby they enjoy ('debauchery'), and they treat other people (including some women) as essentially disposable.
That makes me uneasy, but what about it specifically would you call "immaturity?" It seems that you might mean that it's empirically immature, in that it sounds like the dream and the description (and, hey, this being the internet, it might well be a fantasy) of young people without much life experience.