Huh? Sollecito clearly had NO trouble accepting it: that's why he felt the need to explain it , presumably.
What you and those you consider 'insightful' are missing is that an innocent Raffaele would also have need of explaining to himself and others how Meredith Kercher's DNA could have been on the knife. He could think of only one incident that might have caused it, a time when cooking when he brushed Meredith with a knife and with Tizano having told him in the previous diary entry that the knife may have been taken to the cottage by Amanda for use cooking there it became the only possibility he could think of: he 'must' have had that knife in hand instead. Being as the knife was a common cooking knife that could be found in just about any kitchen in Italy and wasn't even his he'd have no reason to recognize it. He also wrote this in a letter to his family that he started using as a daybook of sorts and never tried to deceive police or courts with it. It wouldn't even have become known had not police illicitly seized his diary and then leaked the contents without authorization.
On the other hand Stefanoni's lies were to the court. There's no 'innocent interpretation' of them, she deliberately tried to deceive the court, she tried to hide the evidence of her malfeasance and has managed to conceal the majority of it to this day.
On contamination in particular here is Massei on her testimony before his court:
Massei PMF 219 said:
With respect to laboratory contamination, she stated that she was not in possession of any data referring to such contamination, and emphasised that if all procedures recommended for good laboratory procedure are applied, this would have cancelled out [i.e. prevented] the occurrence of contamination. She also explained that in performing the various analyses on the biological traces in question, there was no anomaly found which could have caused such a [231] contamination, and she gave evidence of the presence of a whole series of checks [controls], precautions and procedures, intended so as to eliminate this risk.
She is outright lying about there being 'no anomaly found' which you can see
here. The bra clasp itself had numerous alleles that she tried to hide the existence of, which you can see on this chart
here which was generated from reading
these electropherograms. Very simply the first column in the first link shows the alleles that Stefanoni reported, the second the actual number of alleles found above the 50 RFU threshold, and the third the number of ones she 'missed.' The other two links show those alleles on the electropherogram, all of which are larger than the grand majority of the alleles found on the kitchen knife where only a handful exceeded 50 RFUs.
There's lots more evidence of Stefanoni's lies and malfeasance, which is why
in the end this case can end only one way. The ones like yourself who think contamination a rare event need to realize that with low template DNA analysis that's not the case at all, it's
inevitable, even Dr. Balding agrees with that.
Here's something that you, Bolint and Sherlock (amongst others) need to take into account, specifically this but the entire page should also be read. Perhaps then you and the others will be able to understand why top scientists in this field like Drs. Gill and Budowle disagree with your assessment of the likelihood of contamination and the reliability of this evidence:
Conti-Vecchiotti Report: LT/LCN section said:
3.9 Limitations of LCN Typing
Some of the differences of LCN typing compared to conventional STR typing can affect its utility (Gill P., 2001; Budowle B. et al., 2009).
Due to the small quantities of DNA contained in LCN samples and the extreme sensitivity of the method (due essentially to the “optimization” of the PCR and capillary electrophoresis protocol) levels of “background” DNA as well as DNA from casual contact may be detected; thus profiles possibly emerging from these analyses may not relate to the specific case being examined.
In addition, Budowle B. et al. (2009) assert the need to inform the International Scientific Community of the limitations and problems associated with LCN techniques, so that all those involved in a specific investigative or legal case are aware of the risks and limitations which can affect the results of the investigations. Publicizing the potential of the application of LCN typing without describing its limitations is not a responsible role for the forensic geneticist to take.
In this regard, the essential aspects to remember are the following:
1. LCN typing is not a reproducible technique, and this limitation must always be well-emphasized in the reports;
2. contamination from handling is possible, and this possibility must always be considered;
3. a concentrated sample can provide better results in an analysis than replicates which use allele redundancy for interpretation;
4. the number and type of controls used needs to be clearly defined, and to these should be attributed a quantitative or qualitative reliability;
5. to date, interpretation guidelines have not been well-defined, and those which exist only relate to samples from a single source; mixture interpretation has not yet been validated;
6. contamination or allele drop-in may have different sources;
7. due to the increased sensitivity of the method, secondary transfer cannot be excluded as a possible explanation for the results obtained from LCN typing;
8. STR kits, reagents and other materials may not have been subjected to effective quality controls to detect possible contamination from extraneous DNA;
9. statistical interpretations and supporting data for the calculation of probabilities need to be better defined and developed to address the uncertainty associated with LCN typing;
10. as the analysis provides results from very small samples, the material origin of the DNA cannot, to date, be inferred.'