I am wondering the same thing. The statement about dating his own daughter if she wasn't his daughter is an explicitly hypothetical scenario. Implying that she could pose for Playboy if she wanted to isn't anything bad either.
Would it have been more appropriate to say that he doesn't think that his daughter is attractive and that she would be better off by covering her face with a paperbag all day long?
Maybe the creepy thing is that an old man wants to date women who are half his age or even younger.
For me it's more the repeated comments and acts from him about this. In another instance they were asked about the favorite thing they have in common. Donald Trump answered "sex".
Repeating an innapropriate joke over and over and over makes you wonder. Then there's that picture posted above where she's cupping his face. Or when he greeted her on stage like this:
You're only feeding into your own confirmation bias here. The photo of her sitting on her father's lap is from a Vanity Fair photoshoot, and then you have a screengrab from the RNC when he greeted her on stage, shot at the perfect moment and from the perfect angle to make it look inappropriate. You're digging way too deep into this because of a few jokes Trump made.