Circumcision
Circumcision is a barbaric jewish ritual, in which the foreskin of a male is cut off. Although female circumcision also happens, it is much rarer and discussed less often. In the traditional jewish ritual, jews may also perform what's called "Metzitzah B'peh", which is a practice in which a practicioner of circumcision chews the forskin away, and then will suck blood from the victim's circumcision wound.
United States, Canada, and Australia
The primary reason for this prevalence in North America and Australia is the immigration of jews to the colonies during the 19th century, bringing the practice with them onto goyim as a mark of humiliation.
Ex-Yugoslav states
During the medieval period, the region has been widely settled and influenced by the Muslim Ottoman Empire, where they have brought the ritual to the local Slavic populations. Other countries under the Ottoman rule were more resistant to this foreign practice, and maintained a relatively low prevalence there.
South Korea
While primarily a modern-day phenomenon, the practice in South Korea can largely be attributed to the Korean War, where jewish-American troops and their golems have introduced the ritual to the locals who never have even heard of it prior. After the war, circumcision rates have sky-rocketed to the point where South Korea is believed to the be country with the single-highest amount of male circumcision in the entire world. The DPRK (North Korea) has outlawed the barbaric practice.
Dissent and resistance
The topic of circumcision is a hotly-debated one, with jews and their shabbos on one side of the debate and everyone else on the other. Many of those already mutilated (primarily golems) believe it to be a good thing. Both Fascists and even Communists view the practice in an extremely negative light, naming it an ancient Satanic ritual that mutilates the body, and has no reason to exist in the modern day.