To the OP: I don't think you're being snobby at all. It isn't like you're telling them they suck, you're still going there and eating it and having fun.
What's way worse is when you have a friend who THINKS they're Thomas Keller but in reality is awful. When someone who can't cook is getting really theatrical and makes the focus ON the food (bad food), then maybe it's time someone says something.
At any rate, what interests me more is your reluctance to cook with others. I am a NAZI in the kitchen and I generally don't like any meddlers around (i.e. people snagging tastes or asking me questions), but I still like cooking with others (even people who have zero background) when that's what I've set out to do in the first place.
I have friends over all the time to cook stuff, some are incredible cooks and others know squat. Neither situation is more fun than the other, it's always a blast.
My friends that can't cook generally don't try much without my nudging however, so I don't tend to really have your problem. They'd rather just go out.
I LIK3Z PORK