Optics.
People are supporting Trump to stop PC madness, to stop amnesty, to restore America's military and economic standing, not because they want a dyed-in-the-wool conservative.
He's the GOP-e's dream candidate and they still don't like him.
Cruz 'gets it' on the complex situation in Syria, regarding Russia's broader (expansionist) agenda there, and elsewhere. Trump either doesn't or is in cahoots with Putin on it.