The Presumption of Innocence
According to the U.S. Supreme Court, the presumption of the innocence of a criminal defendant is best described as an assumption of innocence that is indulged in the absence of contrary evidence (Taylor v. Kentucky, 436 U.S. 478, 98 S. Ct. 1930, 56 L. Ed. 2d 468 [1978]).
A defendant is found "guilty" or "not guilty" by a jury. If the verdict is "not guilty", it is not unreasonable to interpret that as confirmation of the presumption of innocence of the charges brought against him.
To argue to simply dispute another's argument, rather than seeking truth is rather nonsensical.