>>220398 (OP)Protestant work ethic, internalized through being raised in a culture that glorifies working and achieving material success (because it has to in order to perpetuate itself). NEETs, hikis etc break that cycle by not following the programming and "just" being okay with the minimum necessities to live and not working more than they have to to get it, if at all. Shaming people like that for being unambitious is just crab mentality or projection because most people who are caught up in the rat race hate it themselves and might see NEETdom as an escape.
As for why a NEET/hikki might actually be unambitious or lazy, I think many people start out by doing absolutely nothing because they are exhausted from trying to live a "normal" productive life. But after a while it becomes a rut and hard to break out of, like a kind of depression maybe. Once you lose momentum it's incredibly difficult to get it back. Perhaps that's why many NEETs seem like they are just rotting away.