Nobody *enjoys* causing pain to infants, but one cannot simply discard all medical procedures just because they hurt. The benefits of vaccinations, for example, are obvious and well documented. Yet they also hurt. But we do them anyway.
Why is the USA the only advanced nation to do it if it's a matter of medical care? It's custom. Dangerous, harmful custom that isn't questioned because it's accepted as a cultural norm and myths about health benefits have settled into that culture.