Salams. Why is it that children are born uncircumcised? Why does Allah leave that piece of skin there? He could have created us without it.
Walaikumussalam
I haven’t come across anything explaining the reason behind it. Allah knows best.
The medical experts might be able to shed some light on this. However, maybe it is due to test the people whether they obey Allah’s command by following his instruction to cut it or not.
Or maybe because when you buy some expensive product, it will come with proper wrapping. Similarly, That part of the body is extremely sensitive, so Allah kept it protected.