Ok, let me be clear in that I'm not taking either side on this issue but want to approach it from both.
The Table Rule perspective:
Jerkwater Q Nimrod here has been informed of the rule and obviously can't think enough of the seriousness of the game to make an effort to toe the line.
The offenders prospective:
These Ubergeekwads are artistic, but I'm funny, I’ll show them I can still have a good time but be very clear that I'm not happy.
Who's right and who's wrong - everyone involved.
Like all legal issues (and even though this is a table ruling - it’s still a legal problem) the truth and the fix lies somewhere in the middle of all that has been posted. To all that see this ruling as too draconian and that the DM should shut up and let him play - sit down and be quiet - the player was informed of the rule in advance, agreed to the ruling, at least in theory by playing and still chose to make a complete fool of himself. The player should have sought help, or at least approached the matter in a more mature manner.
For those that believe the DM is absolutely right in this, sit down and hang on. As a DM it is your job to make sure that players have fun, having a miniature does do a lot to increase the visualization, but to categorically smack someone down for a lack of artistic ability and then to publicly humiliate him in an electronic format is JUST AS IMMATURE!! While I agree that you should have taken action and that the actions of your player were wrong, do not ask for help by believing you are already correct in your actions. If the player stated that he had problems with the rule, before he came to the table to play, why did you let him come in the first place? Were you hoping for a confrontation or did you expect him to bow and scrape before your artistic masterfulness? /cheap shot yes, but your treatment of the player was just as cold, point made?/
This entire episode could have been taken care of without elitist attitudes, immature protests and wasting time of all involved, if you would have just approached this as adults, sat down and talked about your differences and the BEST course of action to solve them. It amazes me that in a game that is built on social values how uncivil the players can be at times. The hammer of the gods rests; flames to be rebuffed and retribution is almost assuredly on its way!