Nope, if Cruz supporters are conservative and support the ‘only conservative running’, as they love to brag - why go to an open borders, pro-amnesty candidate? Anyone truly conservative wouldn’t.
So one of the 2 premises is wrong. Either Cruz is not conservative or his supporters are not.
Or both.
A single issue voter are we? Hmmm. Well whatever, everyone can believe what they want. You sound like a Trumpster. Black an white for others, but all sorts of shades of grey and excuses for your guy.