I'm frustrated with him, not because of his attitude about mechanics-before-all - that's not the type of game I want to play but more power to him if that's his preferred game - but by his attitude of "this is the right way to play and everyone else is wrong." I won't sum up the discussion here (check the link if you're interested) but I'm astounded at the naivete displayed.
A game is played for fun. There is no other reason to play. Anything that makes the game more fun is the right way to play the game, and anything that makes the game less fun is the wrong way to play. That's it. That's the whole kit and kaboodle. In 3rd ed. D&D there was even Rule 0 printed in the Dungeon Master's Guide that said as much, in nearly those words. Whenever players would complain about my rulings, I loved whipping those out: having fun is in the rules, bitches, and Monte Cook says I can change them to make the game more fun.
This is where my beef is with this guy: there's no acknowledgment that what constitutes "fun" is different for different players. There are many players, players I respect, for whom fun is number crunching, building a powerful and/or intricate character, and they rely on the rules to be able to play those characters. A GM who arbitrarily changes the rules on that player has negated the players' ability to play that character, making the game substantively less fun. Any GM who wants to maintain fun for these players has an obligation to run the rules as written (including house rules) and to do so consistently.
On the other hand, for many players "fun" is getting into character, portraying dramatic situations, and roleplaying them out. Often these characters have little interest in dice or character stats (I know one such player who challenges herself to see how long she can play a game without actually writing up a character sheet. I believe her record is nearly two semesters). For these players, being forced to roll dice for what they're doing as a character breaks the scene and thus breaks fun. Any GM who wants to maintain fun for these players has an obligation to put story and character before mechanics.
Now here's the kicker a lot of gamers don't want to acknowledge: both styles of play are equally valid.
A gamer who likes mechanics is guilty of nothing more than playing the game written in the book. A gamer who ignores mechanics when they're not needed hasn't done anything except tell the tale the mechanics exist to support. You cannot deride either faction, regardless of which side you come down on without doing disservice to the game as a whole, and inded to the gamer community. Doubly so because most gamers will find themselves somewhere in the middle (it's like sex that way).
Instead of arguing over how a game "should" be played, gamers should acknowledge that there are a variety of styles in which games are played, then find the games that match their playing style. GMs should tell players how they tend to run games and let the players decide for themselves if that's the sort of game they want to play.
This is as true for larps as it is for table top games. When I tell potential players about my upcoming 7th Sea larp, I'm pretty specific about what it's about: adventure, swashbuckling, and personal development. Games will focus on PC interaction and cooperation. Intrigue will be a large factor in the game but politics will not be. Rules will be light and used only where needed, largely because the GMs are still learning them and they're unreliable.
A living campaign is slightly different, though only on a matter of scale. Some living campaigns are very strict about rules, while others are very loose. When someone signs up for a living campaign, they should have a sense as to the game's style, but they must also acknowledge that because the game is being interpreted by dozens, if not hundreds or even thousands of GMs, that there is an inherent variability. So what should the player do? The same thing he would do for a home game: talk to the GM about what type of table she runs. Ask her if she requires people to roll social skills for IC conversations or insists on knowledge checks for things the player believes the character would know even if the player knows OOC. If you don't like the GM's style, find another GM to run that game. If you can't ever find one, you may be in the wrong campaign.
Not every character is right for every game and that means that sometimes a player isn't right either. Or more accurately, the game isn't the right game for the player.
And once you've committed to a game, don't keep arguing about how it "should" be changed. Just shut up and play the game the rest of us are playing. That's why we're all here.