“Since when do we vote according to something a staff member of a candidate does or doesn’t do?”
A candidate is responsible for the actions of his / her staff.
Let’s phrase your post a different way:
Since when do we judge according to something a cabinet member of a president does or doesn’t do?
You cannot absolve Senator Cruz for this action without admitting that he is incompetent in his ability to choose campaign staff, and thus would suffer the same deficiency in choosing his cabinet or other officials in his administration. The fact that he reuses (thus far) to dismiss those responsible speaks volumes ... And then there is also the part that Rep. Peter King played in this fiasco.
You can go ahead and place any value you'd like on a campaign staff member....who have also been known to defect to another candidate......so no I do not hold a candidate responsible in a campaign run. An no I do not hold Cruz responsible for his staff as if this was a Cabinet position.....not even close.....it's a campaign run and that's all it is. It's not as though he's been sworn in or accountable to us in any way...it's HIS campaign to do with as he wants and I give hi lots of room for good work bad work and anything in between.....for the win!
You see I do trust Cruz on the issues he's stood for and I chose him based on those positions.....not on who are how he manages....of which he wouldn't be where he is today were he not doing a lot of things right.