RPM is a "canned" program, where instructors have to use the music and routines that are given to them. It takes the individuality out of indoor cycling. They tried it at my last gym, and it caused an uproar. It was thrown out after a very short time. My personal take is that gyms mandate this, to avoid instructors doing any "contraindicated" movements, as well as to even the playing field between instructors.
I would look for another gym, or get a trainer for your bike and work out at home.