The statement 'the charges were not based in fact' - is a statement by the ACLU, and there's no reason to believe that they are objective about the situation, we don't know what happened.
Maybe they were too aggressive in their laying of charges, if so, hopefully the will be thrown out and authorities will have a closer look, sadly, I doubt anything will come of it.
Also - the 'protestor' was carrying a weapon and acting directly against state authorities. If someone in my neighbourhood had a gun, was standing on the street trying to prod police officers, I would definitely want the police to be checking him out. That said, I don't know if he was actually breaking any laws.
The line between legal/legal and appropriate/inappropriate is really thin. Also, why everyone needs to be carrying guns all the time is beyond me.