You are fully within your rights to decline to listen to Mark Levin. For his part, Levin is empowered to preach his conscience so long as he can hold the audience.
I have no data but I conservatively calculate that he must be grossing well over $12 million a year just on his television project which is about to triple in programming, he has sold over 1 million books, and he has about the number sixth rated syndicated radio program. In addition, he is editor-in-chief of Conservative Review and the leader of Landmark Legal.
I believe he is a movement conservative and quite content with his revenue stream, with the size of his audiences and the scope of his influence in many endeavors.
As a long term listener and short term tv viewer, I am well aware of where Levin stands. Even as a Cruz supporter for a very long time, I did not approve of the way Mark brutalized a fellow Republican. He lost me when he didn’t adhere to Reagan’s rule. I’ve tried to listen a few times since then but couldn’t last through the first hour. I’m surprised he hasn’t lost a large portion of his audience.