I don’t really understand your last sentence, but I wonder, why is it ok that Cruz did not immediately denounce the ad done by the PAC (even though Cruz did not place the ad), but it is NOT ok that Trump didn’t immediately denounce David Duke’s endorsement?
I disagree with your implicit assumption that I think it was wrong of Trump not to denounce the non-existent Duke endorsement, especially since Trump had just disavowed Duke expressly just two days before.