They get their marching orders from the DNC via the network executives.

“You forget late-night used to be a great avenue for politicians to meet the public in a nonconfrontational situation,” Federman said.
“It was always a safe place to go to get your message out and to sort of humanize yourself,” the “History of Standup” author said.

Changed the nature of Late Night Television in order to whip up a frenzy against Trump for four years straight.