Yes, I think you are right.
Levin has spent much of this election cycle being careful not to get too involved in anyone's camp, but recently as Trump responded to Cruz's poll rises with the same type of attacks that Trump has smeared other opponents with, I think Levin decided it was time to speak up and not just to his listeners, but to his colleagues who he thinks should be telling Trump that using liberal attacks against conservative candidates isn't going to be tolerated by conservatives. Go join the Democrat Party if you're going to pull that kind of nonsense.
very good