The bigot who wrote the piece that you linked never explains the actual reason for doing this to a child and insults “white people” instead.
I respectfully disagree. “Culture” can, and frequently does, mean the origin of a custom is obscured by centuries of history. They do it because they have always done it. The author all but says so.
The story is told about a young bride who invites her family to dinner. She plans to serve a family favorite, a ham. While in the kitchen, her husband sees her cut the end off the ham and asks her why she it. Her reply was that that was what the cooks in the family had always done, but it raised her curiosity, so first she asked her mother, who said that was what she had seen her mother do. And so it went, from daughter, to mother, to grandmother. When the entire family had gathered, she asked her great grandmother why she had always cut the end off the ham. Great-grandmother’s reply? “So it would fit the pan”. The reason had been lost in years of “custom”.