People often make alt accounts to just further their own, singular viewpoint, or to shill, spam, etc. I don't believe that manipulating the forum with alt accounts falls under the category of "free speech." Its dishonest, capitalizing on the goodwill of the community & shouldn't be tolerated.
Simple! Regardless of what he's done already, there's definitely a way to know the truth - "see, the truth is like a lion, it fights for itself"
Just because he's doing it and not getting caught doesn't create the validations that he's doing the right thing..