1) MBP is not a requirement for milah, around 250 years ago there were rabbonim who were against it and telling people to use tubes/pipettes.
2) If MBP is not a requirement, then if there is a backlash against milah causing health issues/deaths, then it makes sense to stop a practice that is not required so it gets people off our backs.
3) The Constitution is not at issue here. It is against the law to bring human sacrifices, even if it is part of some religions. If something causes harm/death, then the 1st Amendment will not protect you.
4) As for your claim that most/many do perform MBP, I can only tell you that you are mistaken. I can’t reveal identities, so I can only urge you to actually speak to rabbanim. I have. Only chassidim and a few hard-core UOJ-RW-etc. do MBP. IIRC, even Briskers do not do MBP.
5) I stand by my claim that calling this the worst gezeirah is stupid, it is.