They tell the audience when to laugh?! Wow, that's cheesy. Really cheesy. On a sitcom, alright...but not for a show like that. Leno didn't have a laugh sign, did he?
I can only speak for the Letterman show; earlier this year my wife went to a five o'clock taping with a few of her friends.
They were all surprised to see how orchestrated the whole event was.
An incident that did bother me was when Michael Richards blew up and was yelling racial insults. Jokes like that, IMO, show an underlying mentality of hatred that goes beyond trying to get a cheap laugh. I really liked Kramer, and that kind of ruined the show for me.
Well, switching gears to racism; I understand what you mean. There are the overt forms, like the Kramer incident and there are more subtle, almost subliminal types:
One that comes to mind is the series of (3 or 4) Brinks Home Security commercials.
"All" of their commercials show a pesky "White" male breaking into a home. That's interesting,
I'm sure they know all criminals aren't black, nor are all of them white.
Jokes like that, IMO, show an underlying mentality of hatred that goes beyond trying to get a cheap laugh.
As I look into Letterman more (I've never watched his entire show, just clips) I realize how accurately your "underlying mentality of hatred"
statement applies to him. When I see how he treats people he doesn't like.