It seems like the overwhelming majority of games that are open to the general public are for PvP and not against AI (which personally suits me just fine), and that most of the comp stomps are played amongst closed groups of friends.  So, if you really want to comp stomp what you might consider doing is (1) hosting your own comp stomp game with a title like "all welcome vs AI" or (2) joining game channels for private comp stomps and asking the people nicely if you can join them against the AI.

As a player who has to fight against trolls on a day-to-day basis on ICO i feel your frustration.  It is a real shame that some players come on for the sole purpose of making it hard for other people to play a game.  I think that the best way to combat trolls is to out troll the trolls.  Basically, hop online, make a name, pretend you're a "smurf" (vet pretending to be new) and then trash talk everyone in sight.  The more profanity you can pack into one sentence the better.  At this point, you've probably got everybody on ICO worked up and their panties are in a massive bunch.  The best way to handle this situation is now switch accounts to take some of the heat away from you, and then try to sneak into the lobby when everyone is looking for the smurf.  You are now incognito.

Hope this helps!