I don't like talk radio shows like Howard Stern's because they're stupid and mean-spirited. I don't enjoy seeing people humiliate themselves, or being humiliated by others. And I don't find that funny at all. In fact, I find it repulsive. Yet some people really think these things are hilarious, and they love Howard Stern's show.
I can't stand watching Bill O'Rielly because to me he's just a blowhard and a bully, and I find nothing funny or entertaining about watching him try to humiliate other people just to puff up his own ego. Yet some folks love watching him "rip apart" a guest, and get a cheap vicarious thrill from it, even.
I never thought comedians like Don Rickles, or Jerry Lewis; who insulted other people for laughs, were funny, either. I always felt bad for the people they insulted and angry at them for being such arrogant jerks. Yet some people found them hilarious, and they were well-accepted comedians all their lives.
It's not that liberals don't have a sense of humor. It's just that they tend not to find the more vicious insults and slander that seems to entertain such a large conservative audience these days, funny. I think they don't find it funny because basically, it's not funny. It's just nasty, and ugly, and mean-spirited. And I don't understand why conservatives are so drawn to that crap.