I think that the "fantasy = humor" thing sort of started with something I said, and I just want to be clear that it isn't at all what I meant.
Fun writing helps to suspend disbelief, so if absolutely crazy and unbelievable things are happening, a fun - almost humorous - tone helps the writer to achieve that. But I didn't at all mean to imply that just having "fantasy setting" fits that description. And even then, I didn't mean to say it was ever required. Just want to be clear.