Circumcision also helps prevent some diseases. That's the reason it was started to begin with.
Nothing that "Bathing" doesn't also prevent. The problem with this rational is that it was basically formulated by circumcised Christian and Jewish doctors to rationalize the fact they'd been doing them routinely for several decades, to put a scientific veneer on a practice that was basically just a cultural/religious practice.
Advantages and disadvantages are a wash. The pain part has to be pretty trivial compared to having just been squeezed headfirst out of a hole that normally would just accommodate something be the size of their own little baby leg.
I do agree that this is stupid and they'll have a Hell of a time making it stick, but in the 9th Circus, who knows.