Sorry if it comes across as an attack on your lifestyle. It isn't meant to be. If you find extrinsic motivations morally suspect, then let me assure you I believe your motivations are entirely intrinsic and pristine.
But regardless, there are such things as trends. It isn't presumptuous to assume that people do things for the social benefits. That's just being realistic. If it builds their social network, increases their status, widens their career prospects, makes it easier to find a better mate... perhaps they should be doing that thing, whether it's running an ultramarathon or doing a 6-hour headstand in a park. What does it matter?
Except that if 6-hour headstands become the hot new thing that every young professional seems to aspire to, I'm going to ask about whether "society" should be glorifying something that's obviously going to lead to neck damage versus, say, a nice 6-hour foot race. That's all.