Well, why indeed. Really, he could have made a short, clear, simple denial for the benefit of the LIV he may need votes from one day, and then dropped the subject. He won't let it go -- over, and over, he complains he's being smeared and then smears Trump. It really is not him at his finest.
He has denied it, over and over he has said its garbage. That should be enough.
When NE posted this, it was Cruz who responded to it by attacking Trump for it. He could’ve simply ignored it