I think that's a false equivalence. I do think people have bought into the whole, "I'll abolish the IRS", and everyone knows he won't/can't do that. But in that sense he's like every politician who's ever run for office. They've all promised things they know their base wants that they know they can't deliver.
Trump is orders of magnitude beyond that. Cruz has never said that he could shoot someone in the middle of the street and not lose any voters. That's because it wouldn't be true. But Trumpers were actually proud to stand up and agree with Trump! That's just not normal candidate support. That's way beyond. I have voted in every general election since Reagan and I've never seen anything like the "fierce loyalty" that Trump gets.
So you can say Cruz also has some unreasoned support. But it's not cultlike in the same sense as Trump supporters.
I'm guessing that you don't spend much time among hard-core evangelical Christians? The cult-like following of Cruz has nothing to do with abolishing the IRS, and more to do with his shades-of-theocracy persona. He panders to that crowd with his Tent Preacher shtick, and some are eating it up, in very cult-like fashion.