How we cite our quotes:
"Bald?" I said.
"Bald as a boiled egg," my grandmother said.
I was shocked. There was something indecent about a bald woman. (3.15-17)
Some of the things about the witches aren't really unattractive, they're just... different. Granted, a human being with claws is a little odd because it reminds us of an animal, but a bald woman? There are plenty of those. Heck, two of the best female contestants on the first season of The Voice were bald, not to mention America's Next Top Model.
I kept looking at the hand with the missing thumb. I couldn't help it. I was fascinated by it (4.15)
Grandmamma is missing a thumb (from an encounter with a witch, we're led to believe). But our narrator isn't grossed out by this. Stumpy witch feet? Yeah. Missing Grandmamma thumb? Nope. We wonder if the situation were reversed, and all the witches were missing thumbs and Grandmamma was missing her toes, would the narrator's reactions be different?
I simply cannot tell you how awful they were, and somehow the whole sight was made more grotesque because underneath those frightful scabby bald heads, the bodies were dresses in fashionable and rather pretty clothes. It was monstrous. It was unnatural. (7.17)
Contrast is important here. The witches are ugly, but they're made even uglier because their disguises are pretty. Like, if you put Voldemort next to Kreacher the House Elf, he might look like Brad Pitt.