Maybe this is a British thing, but it smacks a bit of Taking Oneself Too Seriously, which is a capital crime over here. For some reason the the idea of a bunch of earnest, self-ascribed "rationalists" coming up with their own rituals just makes me cringe.

Probably because the result of people taking their lives seriously is often cringe worthy.

But the lives of people who don't take their lives seriously are generally cringe worthy as well, it's just that we've ceased cringing because we've become inured to the usual ways people misspend their lives.

I think the latter is the much more certain and prevalent waste of human lives.