The poster said “lots of Cruz supporters” not all of them. We all know there are a few blind dead enders supporting Hillary by their continued Cruz support.
I very much doubt there are any Cruz supporters to speak of who are actually supporting Hillary.
They may not be supporting Trump and might be planning to sit on their hands...or vote for a 3rd party. But that's not the same thing as supporting Hillary.
Personally, I've committed to supporting Trump -- with the usual reluctance associated with most Republican nominees (if I could vote for McShame, I can vote for any GOP candidate).