I don't think anyone said it yet but I think the real answer is that we don't punch down. So much humor is just making fun of someone different or less fortunate than you, and we basically totally avoid that by...just not doing it. It leads to a different brand of more absurdist and or observational humor but (at least to me) it's more funny because it's something that pretty much everyone could laugh at. Comedy is a social thing and when comedy isn't leaving anyone out of the joke it's funnier. I think at least.

Also