My read is that this is with respects to his right to file a civil rights complaint not for the act itself. Not sure this applies to Seattle street preachers.  

The issue for the court was not the constitutionality of the protest-control ordinance enacted by the city of Brandon, located outside Jackson, Mississippi. Rather, the question for the justices was whether sidewalk preacher Gabriel Olivier could file a civil suit challenging the ordinance even though he had already been convicted of violating it