I don’t contest that at all. But the pathologist’s “expert opinion” didn’t change the fact that tape had been placed on the victim’s head. His claim that the tape was placed post-mortem is just about as valid as another expert witness’s contention that a heart sticker had been placed ON the tape. Neither changes the fact that tape had been used on a child’s head. Again, if there’s a reason for taping a head post mortem, I might see things differently. Reason—pathologist’s testimony or not—says the utility of the tape existed only pre-death.
I gave one possible reason earlier that whoever put the body there put duct tape on the mouth in order to set up a fake murder, and draw attention away from themselves. I could reasonably believe that someone who had another die in their custody, but they did not murder them on purpose, would want to set up a fake murder to keep the police on them.
Its the physical version of saying “I think satanists or a gang did it.”