Someone should say “OK, then lets arrest everyone who comes in a mask to the next riot and we’ll confirm your theory, Herr Riech.”
Actually, that sounds like a good idea, regardless of what theory as to the identity of the rioters. One of the causes/enablers of violent behavior in mass demonstrations is the feeling of anonymity. The masks/hoods/uniform clothing etc. support that feeling. Strip the rioters of their faceless, nameless status and there is less incentive to misbehave. Plus, the bringing of masks (and other riot weapons/armor) shows premeditated intent “to cause an affray” or conspiracy to commit a violent crime.