You are offending a poster; I see this has to do with a rule here (even if I don't understand why defamation of people who are not posters is allowed).
What I said is obviously true, so your claim is disingenuous and unfounded.
Then, your stating that something is "significantly more important than the shoe prints" is actually already off topic, because possible importance of the trace is obviously not the determinant factor: we are, in fact, talking about a delay. The forensic basically said "we can test it, but we need to destroy the item"; the prosecution said "so let's wait, we can always do it later".
Now, the first rapist, Rudy Guede, was sentenced with a short trial in the preliminary hearing. A semen stain would have been unnecessary against him, but also illegitimate because his choice of fast track "freezes" all the evidence, no evidence against him can be added.
We know that on the other side, Sollecito's defence - by his own admission - delayed as much as possible the request to test it.
Now, your comment about protecting alleged "incompetent inspectors of the ILE" is obviously nonsense because those who refused to test the stain were not the prosecution, they were the judges: Massei's court (it was requested at the end of his trial, that means after the testimony and evidence discussion phase), then it was refused by Hellmann-Zanetti, and, the request is opposed by the Kerchers; and now it's rejected also by a Florentine court, whom nobody in Perugia knows (hope you are not believeing a Florentine court protects some obscure Perugian investigators).