Counterpoint - you’re cherry picking. He also invites left wing guests and gives them the same opportunity to speak.
He has a vast audience because a more centrist view of things appeals to a huge # of people. Your description of his audience is reductive and close minded. Yep, there are people who fit that description. And there are going to be others who fit every other description you can write down, too. Why? Because hundreds of millions of people listen.
Now do fox and MSNBC!