Not everyone likes skinny jeans. The people that do like skinny jeans like it because it looks good on their body, and in this day and age people tend to like skinny people, so skinny jeans merely contour the body.
No, Justin Bieber likes girls who are all sizes, medium, large, skinny, and in between. It probably doeasn't matter how tall the girl is, either. The only thing that matters to Justin Beiber is who they really are.