Yes, he was sort of an apologist for Trump, a deflector, as you wrote. He's become intellectually dishonest about conservatism, the Republican Party, and Trump. He lost credibility when with many people when he became a woozy about the liberal statist, Trump.
Mark Levin is not fond of Trump (maybe because he's not a golf buddy.) Levin never fails to point out many of Trump's conservative deficiencies. At any rate, he says he'll still vote for Trump because he can't stand the idea of President Hillary. Now that is a position I can understand, and I might vote for Trump for that reason as well. (I'm still not sure what I'll do...I might write in Cruz.)
But Rush couldn't or wouldn't do that. He's already admitted Trump is not a conservative while praising Cruz (and Rubio as well) as being solidly conservative overall.
He certainly has enough dough that he could withstand the loss of listeners who would stop listening to him for criticizing Genghis Con. But nary a negative word about Trump escaped Rush's lips.
By failing to make even modest objections to any of Trump's many sins Rush threw away his integrity and the loss of millions of formerly hardcore listeners, like me, who now only listen occasionally or have totally given up listening to him.
After years of preaching about always electing a solid conservative he throws in with the least conservative and most morally objectionable Pubbie candidate ever. Oh, how the mighty have fallen.