Bad move, Ted. Insulting a major portion of the GOP base isn’t going to play well.
I don't read Cruz's remarks as an intelligence insult. His claim is that Trump is corrupt and has the nature of a Washington insider by having played ball with politicians his entire adult life, and that once people become informed of those facts, they will stop supporting the corrupt Washington insider, Trump.
IOW, the "low information" rhetoric isn't "low intelligence."
I do agree that Cruz's remarks will (properly) be scoffed at and even taken as an insult by those who are engaged, and choose Trump just the same. I think Cruz intends to alienate this group of voters, just as the GOPe intends to alienate the social conservatives.