If (forgive me) the child had not decomposed before the duct tape was applied, how is it possible that there is no DNA on the sticky side of the tape?
It is not - put duct tape on your arm, rip it off, it will be covered with your DNA.
Even more so, if you were a rotting corpse.
So, who applied it, and when?
Are you arguing that the body found is not Caylee? I don't know why else you are bringing up DNA on the tape or think there was no DNA on the tape. There was hair attached to the tape. It was Caylee's.
That's easy, because the DNA degraded from being out in the elements and humid Florida air. This was discussed very thoroughly at trial.