I also want to know why people don't like things! It's taking all my self-restraint not to bust into entitled author wailing, crying "Why? Why didn't those two people like those stories? Whyyyyy?" while rending my clothes and tearing out my hair.

It's usually balanced out by the "likes," though, and many readers participate both in polls and commenting if they liked the story.

And yes, I think the joke option skews poll results (see here for a recent example).