Yes, human birth is precious, in the same way that any form of life is precious,
That particular teaching is often thought of that way. Actually the "precious" adjective refers to the opportunity to practice Dharma, specifically the Vajrayana, which is rare.
And yet they then turn around and claim that those who don't succeed in this life can take rebirth in a buddha realm where the circumstances are ideal and realization assured. I've never questioned it before, but i would be hard-pressed to see how such a rebirth could be considered "human". So even on that fundamental point there would seem to be some discrepancy and contradiction.
but the human form is definitely not the vehicle for experiencing anything akin to "ultimate reality", any more than a child in a nursery is capable of understanding celestial mechanics or quantum physics.
Actually I've been told that the here and now, this life, is a better opportunity than the buddha realms. For practices like the 6 yogas you need a physical body. Sakyamuni gained full enlightenment while living on planet Earth.
Sometimes I allow myself posts that are wild flights of fancy. Sometimes I stick to what is traditionally taught. I think if you ask an ethnically Tibetan lama, of any sect, you'll find that I haven't misrepresented the idea. I find it interesting that this is the first thing they say to anyone aspiring to spirituality. I assume this is because the view otherwise is universal and pernicious.
Now for a flight of fancy: I believe that if this initial, simple teaching was correctly understood and believed, that it would invalidate 80-90% of western culture. If understood and believed, it is shocking. But nobody
even takes a second look at it.
In the Tantra of the Beautiful Auspiciousness (bKra shis mdzes ldan gyi rgyud), this "Great Primordial Purity" (sPyi ti) is defined as follows:
What is known as "The Great Primordial Purity”
Is the state abiding before authentic Buddhas arose
And before impure sentient beings appeared;
It is called the great Primordial radiance of immutable awareness.