If everyone but Mary can post negative comments without causing a riot then who is to blame for the problems, Mary or everyone else?
It's simple. The person to blame for starting a riot is the one who starts a riot. Posting negative commentary is not the start of a riot.
I trust Matt has learned to enforce his TOS, and to enforce it evenly. I hope Mary has learned not to violate the TOS with personal attacks. We will see what "everyone else" has learned.