Why do boys remove their foreskins in Islam?

It is required acording to their religion.

All mammals with a penis also have a foreskin, it is is an important part of the penis, it contains thousands of Meissner corpuscles which greatly add to the pleasures of masturbation and sex (which is why religious people want to cut it off, to spoil sex). It also protects the delicate glans from drying out and rubbing on your underwear and becoming numbed. Lastly, it allows a gliding movement which makes intercourse much nicer and comfortable for the woman. So if somebody wants to cut off your boys foreskin, or yours, refuse them and RUN.