When Johnny Carson was host of The Tonight Show from 1962 to 1992, he did thousands of political jokes. His target: Politicians -- every one of them, presidents, lawmakers, Democrats, Republicans, it didn't matter.

Why? Because politics is funny. Simple. And politicians are hilarious. From both parties! So, you think Rep. Nancy Pelosi is funny, but Sen. John McCain isn't? You think Rep. Maxine Waters is ridiculous, but not Gov. Chris Christie? Politicians all are so full of themselves, clearly unaware of the meaning of "hubris," convinced that they -- and they alone -- can save the nation. Now, that's funny.

But nowadays, late-night comedians have decided to mock half of its potential audience by bashing only Republicans. No one really knows why networks don't say "Hey, you're costing us viewers -- which means you're costing us money, so stop it." But they don't. They're just fine with talk show hosts ripping half of America.

Look at today's hosts. Jimmy Kimmel goes on a rant about how good Obamacare is -- and how awful people are if they don't think so. Stephen Colbert goes on a profanity-laced tirade targeting conservatives. Only Jimmy Fallon, the highly unworthy her to Carson's Tonight Show has steered clear of divisive nightly rants, although he's being urged to be "more political" to catch up with Colbert's ratings.

There are others, from Samantha Bee, hostess of Full Frontal, to Trevor Noah, host of The Daily Show. And there's Jon Oliver, the very unfunny Brit on HBO's Last Week Tonight. Target audience: Young liberals. Anyone else can, as Colbert might say, just @#$%&* off!

How bad is it? This Detroit News cartoon captures it perfectly.

Over the weekend, Newt Gingrich, the former House Speaker (and a really funny guy when you get to know him), said something's gone terribly wrong with today's entertainers.

"The problem you have with humor in America today is that Hollywood is so enraged at Donald Trump that they can't be funny," Gingrich said on Fox News Sunday. "All they've got is pure anger. And that's what's coming out in this stuff."

Gingrich was spurred to comment after the profane rant Colbert delivered on Monday. "You're not the POTUS, you're the 'gloat-us,' " Colbert said in a joke perhaps targeted at 12 year olds. But then he went after the adults. "Sir, you attract more skin heads than free Rogaine, You have more people marching against you than cancer. ... You're a real prick-tator. The only thing your mouth is good for is being Vladimir Putin's c**k holster,' Colbert said.

Gingrich said the new crop of hosts "think it must be funny because they're called comedians."

"So they exhibit their anger as almost a pathology on late-night television and you're supposed to laugh because, after all, they're comedians," he said.

On Kimmel, the speakers said the very sad story of his newborn son needing heart surgery -- which the host claimed was only possible because of Obamacare -- is "part of the left's mythology" that doctors will not treat uninsured or under-insured people.

"You show up at a hospital with a brand-new baby and the brand-new baby has a heart problem, the doctors of that hospital do everything they can to save the baby," he said, regardless of whether a patient has insurance.

Gingrich's diagnosis of what ails today's late-night hosts: "They ain’t funny ’cause they’re too angry to be funny.”