He is innocent, in the eyes of the law. That means he isn't going to prison, and he isn't a convicted rapist.
It does not tell us with absolute certainty what happened between him and those women.
It may be, as some seem desperate to believe, that some or all of them falsely accused him for personal gain.
It may also be that they were all totally genuine accusations for which the prosecution failed to provide compelling enough evidence.
We can't know what happened. We can't know what Mendy or his accusers knew or felt at any given time, or who is telling the truth. This is why rape cases are so hard to prove.
We all know guilty people go free, and innocent people go down. It's rare, but it happens. Not trying to cast doubt on this verdict - but there is quite obviously a difference between conviction and guilt.