Wait, you're suggesting that physical evidence that does not point to a family member as assailant should be discounted because you "bet" there's more logical reasons it's benign and has no bearing to the case and the suspicions of other people -- including unspecified "professionals" should be considered as stronger evidence -- despite there being no clear, Incontrovertible objective or scientific evidence the family did it?
ETA Incidentally, a full 50-percent of the reasons you cite for their being a logical reason for that DNA being present points to mind numbing mishandling of evidence by LE or the crime lab, particularly LE if you know anything at all about the processing of clothing from a murder victim's body. There would be NO, absolutely NO instance where there should be even the slightest possibility for TOUCH DNA to be transferred from LE to Jon Benet's undergarments. They would have been removed by the medical examiner at their office, bagged and then handed off to the crime lab. The only time they would have been in the possession of LE they would have been bagged and sealed for transport to the crime lab -- and rebagged and sealed after testing.