To be honest applying the word "professional" to Steffanoni and her work in this case is quite a stretch. With regard to your claiming that "if there was a contamination argument that held water, that would have been presented during the trial and the appeals" you must remember that C and V said both the bra clasp DNA and the knife DNA evidence were unreliable. Helliman believed them, 5 judges of the ISC and Nencini did not. None of these judges seem to have any significant forensic DNA background. How else due you explain Nencini claiming that some of the Y-hapotypes found on the bra clasp might be attributable to females. Without such background, how can they begin to understand the nuances and requirements of such technology. Consequently it seems logical that they would give the benefit of the doubt to a state employed "professional". I'm told that in the US, judges who handle such cases have to at least read an extensive manual concerning DNA analysis before trying these cases.
Now I'm not defending the A/R defense teams. I personally feel they did a suboptimal job in several areas. They should have had their own experts examine the information Steffanoni provided with a fine-tooth comb. If they had, they would have come to the same conclusions that Chris Halkides and his colleague did, there was contamination. And in reaching such a conclusion they should have found some way to dumb-down the information so that even an uninformed judge could understand. Unfortunately, they did not.
By the way, this is not the first time a forensic expert has been found to be either incompetent or corrupt. I refer you to the case(s) of a forensic expert in the state of North Carolina. Now, 100's of her cases are in the process of being reexamined because of her corrupt behavior.
I would think people on this board would be more interested in finding the truth than supporting the supposed "professionals" in Italy.