No, it's an unacceptable inference. And the word "Italian" here is particularly unacceptable.
Every trial procedure can be subjected to criticism (and would be better if that's done by people ancknowledged with the system). As for me I always pointed out that - I've not "learned" anything new at all. But this has nothing remotely to do with what the pro-Knoxes do. The pro-Knoxes accuse people of conspiracy, and attempt to place witness under trial and by that way mean to claim "innocence" of the accused.
The pro-Knoxes are delusional and lying on a factual level. It has nothing to do with expressing technical opinions about procedure.
What you say hardly makes sense. Your problems with "credibility" of such things are essentially a problem with your prejudice.
First of all should be remided that Stefanoni wrote to the judge she was ready to release raw data if the judge ordered so (never said "should not be satisfied"); then, indeed she made procedural arguments, she pointed out that the defence experts were able to witness the tests that were conducted within a transparent adversarial procedure (and in her testimony, Stefanoni pointed out that they had been invited to the laboratory if they wanted to access data); therefore, Stefanoni implies a late complaint about lack of documentation could be used as an argument to attack her.
Not just Novelli made the point that evidence of specific contamination must be given by those who claim it: this was also a point of law decided by the Chieffi court on the case; and such point of law is definitive on the case, as for art. 628, it cannot be changed by Marasca/Bruno panel.
To investigate files, Novelli simply did what Pascali did not do, and what defence experts Gino & Tagliabracci also didn't do when evidence was re-opened on appeal, that is go to Stefanoni's laboratory and access the files.
Let's point out that also Vecchiotti & Conti declined the option of having raw data. Vecchiotti explicitly stated so in court, explaining that they would be not interesting to her work.
Acctually, and astonishingly given Vecchiotti's subsequent behaviour, Conti & Vecchiotti didn't even ask for negative controls, diden't even find them within the file (albeit they had been deposited with the preliminary court in Oct. 2008, and their deposit was in the record).
The point of law has been subscribed to by the Supreme Court.
It is just met by rationality. Whenever one claims the occurrance of some event is probable, is supposed to bring evidence about that.
Berti said that it can be useful, not that it is essential. But still this doesn't change the fact that Vecchiotti stated that it is useless; and doesn't change that the defence didn't request them, certainly not with arguments that could convince a judge.
On the contrary, the records say tha they were requested so. Yet you should understand that what the Carabinieir did in 2013 is no argument.
On the Parolisi case, the Carabinieri destroyed the evidence items immediately right away after testing them in the incidente probatorio. On the Peruzzi case, Vecchiotti withold parts of the DNA profiles from the knowledge of other parties and she used the lack of discovery of the other party in order to lead them into a trap. Speculations about alleged "different approaches" in different situations are completely pointless.