Bypass surgery, for example, is not the same kind of "body mod" as a cosmetic nose-piercing.
Somebody needs to study up on the distinction between therapeutic, prophylactic, and cosmetic reasons for surgery.
Routine neonatal circumcision is allegedly prophylactic (actually cosmetic in most cases). Surgery to remove body parts for prophylaxis is drastic and unheard of except in this particular case. Back when they used to remove tonsils all the time, at least they left you alone until you got sick.
It is well-known why routine neonatal circumcision became widespread...early-industrial-age medical quackery, nothing more. Baby girls were not spared; Kellogg recommended dripping acid on their clitorus (of course before they were old enough so as to make holding them down difficult). The objective was the same...destroy the maximum amount of erogenous tissue while leaving the victim mechanically able to procreate. The reason routine neonatal circumcision persists in the US is manyfold
1) men who were themselves mutilated as infants, and don't want to admit that they were harmed, and despite (or perhaps because) having no point of reference since the decision to amputate the interesting structures of their penis was made for them, they decide they prefer an abbreviated organ as a coping mechanism
2)"they did it to me when I was defenseless, so now that I am the one in power I am going to do it to you (lest you get off easier than I did)" (this attitude is is also prevalent in pedagogy)
3) it's $300 adder to otherwise routine births, that insurance pays for. Yes I do think humanity in general and the medical field in particular is depraved enough to perpetuate a useless and disfiguring procedure through pure banal profit motive. Follow the money. When the mutilations stopped being covered in the UK the establishment all of a sudden decided it wasn't so necessary after all.