My understanding of the view is that it is all-inclusive.
That is not, ultimately, a contrived and forced idea of inclusiveness, but rather, the insight into awareness where nothing at all is left out. The Universal approach points to the vast nature and inherit luminosity of the mind as pure awareness. However, the concepts about that are so easily mistaken for the referent and the beliefs that bind us to concepts are deeply ingrained.
It is understandable for a particular school to create conceptual boundaries in order to contain and delineate its philosophy and method, and that is usually accompanied by debate between the lineages, etc. That is, just as a glass is used to keep water from spilling out all over the place and to keep the surroundings out of the water. It is a matter of skill in this case, though. Not easy in a tumultuous world.
The realization of impermanence, (which you mentioned) makes it clear that anything compounded will change and ultimately perish, so that can shed light on any political or religious stance on doctrines and purity in the long run. Yet, one can also understand the desire to retain a teaching or system and maintain its integrity, as well. Compassion works both ways and arises with the object of compassion itself, mutually as a unitary motion.
There has been a tumult of transition for Tibetan Buddhism and it is understandable that there are concerns, disagreements and the like. We can all experience that when it comes to things we hold dear, meaningful, important, pure, etc. In one sense, the dissemination of the teachings, (including the rather esoteric and secret ones) to the West serves to preserve them. In another sense, that process can also distort them and transform them beyond recognition.
Perhaps they should consider consulting Longchen Rabjampa on this matter:
The hidden awareness of natural perfection is everywhere,
its parameters beyond indication,
its actuality incommunicable;
the sovereign view of natural perfection is the here-and-now,
naturally present without speech or books,
irrespective of conceptual clarity or dullness,
but as spontaneous joyful creativity
its reality is nothing at all.
Good Fortune!!!