No, it is not ethical at all. Humiliating someone based on any physical characteristic is a form of body - shaming. Everyone should be respected regardless of their body type, and spreading such stories can cause great harm to a person's self - esteem and mental health.
If you come across such stories, don't share them and encourage others not to as well. Also, promote positive body image campaigns to counter such negative ideas.
Once upon a time, there was a big elephant and a small mouse. The elephant was so large and strong, while the mouse was tiny. One day, the mouse got trapped in a hole near the elephant's path. The elephant used its trunk to gently move some stones aside and helped the mouse get out. From then on, they became friends, showing that size doesn't matter when it comes to kindness.