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.
Rather than focusing on humiliating stories, we should promote body positivity. People come in all shapes and sizes, and no one should be made to feel ashamed of their natural body features.
First, education is key. Understanding that penis size varies widely among individuals and that it doesn't necessarily correlate with sexual performance or masculinity can help. For instance, studies have shown that the average erect penis size is around 5 - 6 inches, and most sizes fall within a normal range.