The surprise to me isn't that this got an R (the rules, as explained above, are crystal-clear and JERSEY BOYS surely must have more than the automatic R requires.) The surprise to me is that we the public still continuously empower such a backwards rating system that permits effusive violence and sexual innuendo but places strict limits on language, among other criticisms of the MPAA.
Words don't deserve that kind of malarkey. They're innocent, neutral, precise, standing for this, describing that, meaning the other, so if you look after them you can build bridges across incomprehension and chaos. But when they get their corners knocked off, they're no good anymore…I don't think writers are sacred, but words are. They deserve respect. If you get the right ones in the right order, you can nudge the world a little.