Everyone has different idiosyncrasies. If the friends of the OP don't want to use their RV toilet, that doesn't mean they are not REAL RVers. It just means they have issues with using their RV toilet. I don't see anywhere from the OP's statements that these people are demanding that everyone else stops using their own toilets.
I say what people do or don't do in the privacy of their own bathrooms is their own business and has absolutely no bearing on whether they are REAL RVers or using their RVs in an acceptable manner.