Totally agree with this - ex-Mormon from the east coast of the U.S.I was born into a very lapsed and non-practicing Mormon family in the desert southwest. No idea what the doctrine is, I don’t concern myself too much with it. All I know is from personal experience. My high school was probably 50% Mormon and all of the gringos in my gym class were circumcised—Mormon or not. The only time I saw a turtleneck was on a Latino immigrant or foreign exchange student.
It’s more an American cultural norms thing than a Mormon thing.