Question about Confidentiality of Discussions with One’s Rabbi in American law

“He doesn’t have to be your lawyer”

WOW…a criminal confesses to the prosecutor and under your theory the prosecutor could not testify.
Actually, he can. There is no atty/client privilege and the hearsay exception of admission against interest would apply to allow the testimony in.

I don’t practive criminal law, but having helped daughter and son in law study for the Bar exams last year I reviewed all kinds of thinbgs I haven’t dealt with in 30+ years

Confession might be inherently part of Catholicism and not other religions, but I think that the law does not recognize religions differently, once an exemption is made for one religion, it will be made for all. A good example is alternate side of the street parking in NYC. For OOTners, there are laws that state that one cannot park a car at certain times on certain days of the week on a specific side of the street to allow for street cleaning. Say, can’t park on left side on Mon, Wed, Fri from 9-12, and on right side on Tues, Thurs, Sat. So what do you do on a 2 day yom tov falling on Mon, Tues? You will have to leave the car on Sun on either the right or left side and get ticketed one of those days. eventually, the city recognized the difficulty that Orthodox Jews faced and canceled alt side of the street parking -for everyone- on Jewish holidays. And so that it would not appear that they were favoring one religion over the other, it is canceled on many holidays of other religions even though they have no prohibition of driving a car on those days. I imagine that the same principle would apply to the clergy confidentiality issue.