
Because it’s part of our religion. I’m not sure what happens if they choose not to, I can’t imagine the results are very dire tho. The thing about religious practices is they are out of the norm for secular culture. The covering of women, abstaining from certain foods, not participating in public society for certain reasons, fasting, circumcision of both male and female children - all of these can be found to be harmful in a health or sociological sense to secular culture
Religious people of a variety of faiths still practice them (be they Christian, Sikh, Muslim, Jewish). Any argument against one can be broadly applied to any other, which is fine as long as you’re willing to concede that no one should be allowed to practice the aspects of their faith that oppose secular society. If that’s what you believe more power to you.