It surprises you there are people who like it? Really? People like Monty Python, does that surprise you as well?
I guess I have different expectations for this game genre. If I watch a comedy film (especially something like MP) I expect some silliness. I generally expect CRPGs to maintain a certain level of seriousness so I can lose myself in the fantasy world, instead of constantly being reminded that this is a game by slapstick humor, pop culture references, or 4th wall breaking. Of course it's a personal preference and as I've said it doesn't completely ruin the game for me, but I eagerly await a mod to make it a little less cartoonish.
