The CSC preferred to trust a prosecution witness, most of whose academic work is not in DNA forensics over two independent witnesses, whose academic work is more relevant. Besides being questionable in its own right, the CSC was trying to rule on facts (through the back door), even though it is not supposed to do so.
If the CSC wanted to make better rulings on DNA it could look to how Australia has dealt with the Farah Jama or the Jaidyn Leskie cases, each of which was the subject of a special enquiry. A former Australian Supreme Court Judge, Frank Vincent wrote in his report on the Jama case: Precisely how it [contamination] may have happened cannot be determined as the deposition of the minute quantity of material involved could have occurred in a number of ways. It is possible to speculate about the probability of transference through various mechanisms, but ultimately pointless to do so.
Judges weigh evidence. They are not expected to be experts in every field of study that is introduced in a courtroom. Regarding C & V, the academics, I think it will be very easy to find many people that do not hold academic work in higher esteem than field work.
Clearly, in the case you reference, the judge reviewed the evidence and accepted that transference was likely through various mechanisms. In this case, C & V have been unable to present any logical argument regarding the realistic transference of evidence. Clearly, the cases have nothing in common.