But is it then okay for one person to selfishly demand that others change their roleplaying style (which they are apparently having fun with) because it doesn't suit their tastes?
I think an important point of my complaint has been lost.
I have no issue running a ridiculous campaign if that's the goal.
In that game, the players decided upon courses of actions that have consequences. For example, they mistreated villagers and sent them out to be roasted horribly by a dragon. As well, they left a cart out by the entrance to the village (to block attackers so they could lessen a surprise) and were shocked when, after a fight, the cart and mule were taken. This wasn't a comedy game, but a normal game.
The whole point of a game is to have a scene described, choose your PC's response, and then learn the consequences of your action choices.
The issue is that, when the choices were made and responses given, they chose actions that would shock the game world.
The issue is that they're cruising for a bruising, but will get upset when it comes.
I GM the way Robert Jordan GM'd (according to his intro to the d20 Wheel of Time): their choices matter, and they're not always easy ones. If they do something stupid, they have to live with it. I'll go easy if I'm the one who made the mistake, but if they pick a fight with a dragon it will fight back. Dragons are dragons. A 30 foot fall is a 30 foot fall.
For that reason there's a sense of accomplishment, and I have players who come back every week. that's the social contract.
Ultimately, I don't want the PCs to get themselves killed, but if they do dumb stuff I have to respond to it.
btw, the three of them decided to set a trap for the dragon by covering a dead bandit in lamp oil so that, when the dragon started eating it, they fired flaming arrows at it so it would ignite. It was clearly and demonstrably a fire-breathing dragon. One of them complained "oh come on, why should it be immune to fire? You're 75% water, but you're not immune to drowning".
No, I'm not. And thankfully neither are their characters!