Let's examine: ChNN and other teacher of Dzogchen point out that for most of us, we will not reach liberation in this life, but in the bardo. Like the Garuda, born fully grown once the egg hatches. How are we to interpret this outside of the teachings on the bardo? As a Christian, or Muslim, or Amazonian Shaman, (or existentialist) you will have your own structured belief about what happens immediately at the time of death, which may contradict bardo teachings. How does this fit with the argument that any denomination of any tradition can also be a full-fledged Dzogchen practitioner? At a certain point, they will have to choose to discard one version, or the other, ---or both will lose all sense.
Christians, and everyone will experience sound, lights and rays in the bardo. If they practice Dzogchen, they will learn how to recognize this experience.
Personal experience trumps belief, even Buddhist beliefs.
It seems all or most of the people arguing for an autonomous Dzogchen are part of the Dzogchen Community, --as Malcolm points out, a very human institution. Are we arguing for a Dzogchen without the Dzogchen Community? Why would we? That's where the teachings are held, cared for, and transmitted. Same with Buddhism. And they are not different. In DC, Rinpoche has us do Tuns and Ganapujas which have very Buddhist, tantric, practices..
Deity Yoga, mantra recitation, seven line prayer, protectors, etc.
Insitutions are impermanent. They develop, flourish and then die out. Buddhism developed, flourished, and is now dying.
Dharma, on the other hand, is eternal.