If you want to characterize questions, not accusations or derogatory remarks, just questions, about a potential candidate’s position as “purity tests” then it’s reasonable to question your position. Don’t you want to know his positions?
By the way, I’ve made no comment whatsoever about Cruz.
I understand that amnesty/immigration is your top priority.
It's not mine, and if a candidate has something less than the "pure" stance of "round 'em up and put 'em on the first boat out," it doesn't mean I won't support him/her.