I'm not sure that "calling out Trump" would have made much of a difference. In the three weeks before the primary here in Florida, you couldn't watch TV or listen to the radio for more than 10 minutes without being bombarded with ads "calling out Trump". But it made no difference.
Part of Trump voters actually think that Trump would make a good president. But I believe an even larger part of Trump supporters are more interested in "sticking a thumb in the eye of the Republican Establishment".
For years, they have been told that only a "moderate" can win in the general election, only to see the moderates lose. For years they have voted for candidates in the House and Senate that promised to end Obamacare, reduce spending, reduce the national debt, etc. only to see them refuse to do those things necessary to accomplish this because it might imperil their reelection.
They are sick and tired of "political correctness", and are pleased to see a candidate who refuses to be "politically correct", even when that particular "incorrectness" is idiotic on the face of it.
Trump would make a horrible President. But not as horrible as Hillary, Sanders or Biden.