By the term "legal innocence" I mean the colloquial use as a synonym for "found not guilty in a court of law".
I am fully aware the courts - at least in the US - do not issue verdicts of "innocent"; the verdict given is "not guilty". As you demonstrate, and as shown by the many definitions of "innocent" in Webster's Dictionary, that word has too many meanings to be well suited for a court verdict.
Again, it is you who are promoting an argument towards me and others. I think that this is based on your interpretation of the verdict of acquittal under CPP Article 530.1 as a verdict of "innocence" whiles a verdict of acquittal under Article 530.2 as a verdict of "not guilty because there wasn't enough evidence to convict" - propositions that I have not stated as my own and do not agree with. If one abandons the misconception that 530.1 is a verdict of "innocence" and accepts that it is the historical baggage of Italy's former inquisitorial judicial system, the "problem" is solved. In the inquisitorial system, judges were assumed by law to be able to devine whether an accused was guilty or not guilty after the judge read the investigative report from the police and prosecutor - the prosecutor supposedly including in the report mention of any exculpatory evidence he had found, with the defense allowed a proforma presentation.
The Italian Code of Criminal Procedure (CPP) used until recently (1988) was one drafted in 1930, during the fascist era. In the inquisitional system embodied in that code, there was an investigating judge who would direct the investigation to "ascertain the truth". He would hear witnesses and experts, perform searches, seizures, and experiments, and could summon the accused for questioning. No defense participation was allowed in this investigation phase. All the evidence obtained in this investigation would be recorded in a dossier that was given to the trial judge, who originally decided the case based on the dossier.
Some years after World War 2 ended, and the new Italian Constitution was adopted (1948), reforms began to be introduced into the inquisitorial system. These reforms, including decisions of the Italian Constitutional Court in the 1970's, allowed the defense opportunities to challenge or contradict the information in the investigative dossier, and there was some development of confrontation of witnesses and adversarial procedures for the trial. However, in most cases the trial phase did not add to or disavow the conclusion reached during the investigation. The defense was forbidden by law to conduct any investigation, and the investigative dossier was not disclosed to the defense until the trial. The trial often turned into an "official reading" of the record and conclusions formed during the investigation, a mere formality. In other words, there was a "presumption of guilt" rather than a "presumption of innocence".
While the Italian Parliament began a major reform to an adversarial, or hybrid adversarial - inquisitional, system in 1988, the reforms were resisted by the regular courts (which are totally independent of Parliament) and the Constitutional Court, which struck down many of the reforms as unconstitutional. Thus, it became necessary for the Italian Parliament to amend the Constitution for the reforms, when passed again, to become law.
The CPP was reformed again in keeping with certain amendments to the Constitution to provide specific legal procedures designed to make the judicial system more adversarial and provide rights to defendants similar to those in the US, UK, and other democracies and conforming more closely to the Convention. However, even this round of reforms met opposition from the courts and the Constitutional Court. Certain types of hearsay testimony and statements by witnesses that were not allowed to be cross-examined were permitted by Constitutional Court judgments, for example, based upon the ideological principle that the judge's ability to seek the truth should not be restricted by the rights of defendants, rights that were foreign to the inquisitorial system which the Constitution Court claimed was basic to the Constitution. In 1997, the Parliament responded by passing new reform laws designed to provide defendant's rights while seeming to follow the Constitution, but the Constitutional Court again struck down these reforms as unconstitutional as before. This battle between Parliament and the courts continued for several more years.
The Parliament decided it would need to further amend the Constitution to explicitly state the intended procedural system and provide for defense rights. Constitutional Law 2/1999 reformed Article 111 of the Constitution by introducing 5 new clauses; these were called the "fair trial reform". These clauses include that evidence in criminal cases must be heard before an impartial judge with the parties present and that guilt cannot be established by declarations of an accuser who has not allowed himself to be cross-examined {the prosecution attempted this in the Knox - Sollecito case by the introduction of the verdict and motivation report of Guede's fast-track trial, which included unchallenged accusations against Knox and Sollecito}.
Parliament then passed law 63/2001 to reintroduce the reforms of the CPP previously struck down by the Constitutional Court. That Court now declared the laws constitutional.
But there were additional reforms passed by Parliament to bring Italian law into alignment with the legal practices of the democracies and the Convention. These are germane to the discussion of CPP Article 530.
The reforms of 1988 intended to eliminate the acquittal for insufficient evidence, which was inherited from the inquisitorial system based upon the presumption of guilt. The Constitution and Convention requires a presumption of innocence (no person shall be considered guilty until finally convicted); therefore, Article 530.2 was introduced, with the intent that one is not guilty if the evidence does not support guilt. However, the wording of 530.2 itself was considered unclear for establishing the required standard for guilt, so in 2002 the Joint Chambers of the CSC decided that "proof beyond a reasonable doubt" was required as the standard for conviction. Parliament confirmed this by passing law 46/2006 which incorporated the BARD standard into CPP Article 533.1.
So, after this rather long exposition the complexities of Italian criminal law legislation and judicial action,
the reason for the strange wording of CPP Article 530 is simply that the Italian Parliament decided to insert 530.2 without deleting 530.1, and the reason was to bring the Italian criminal law system into consistency with the BARD standard. There was no intent for paragraph 1 to be a "better" acquittal than a paragraph 2. It is important to realize that Italy was doing this to convert from a system where an accused was presumed to be guilty to one where an accused was presumed to be innocent until proven guilty beyond a reasonable doubt.
Sources: The frustrated turn to adversarial procedure in Italy (Italian Criminal Procedure Code of 1988), Giulio Illuminati; 4 Wash U Glob Stud L Rev 567(2005)
https://www.researchgate.net/public...Italy_Italian_Criminal_Procedure_Code_of_1988
Gialuz, Luparia, and Scarpa, eds. The Italian Code of Criminal Behavior: Critical essays and English translation, Wolters Kluwer Italia (C) 2014