This thread is rather fanatical posted by an OP who seems to have a blend of Hindu nationalistic, new-age, revivalist and Aryanism beliefs. The OP provides no evidence for why Hiryangarbha is the one and only true of Hindus, and what he does provide are scattered references in Vedic, post Vedic and Puranic literature. However, we find just as many references in the same sources that call Indra, Surya, Agni, Soma, Varuna, Mitra, Vishnu, Shiva, Brahma and any number of the deities the one supreme god. The OP just conveniently seems to ignore this and decided to elevate a rather minor god like Hiryanharbh to supreme god status. It is similar to how Vaishnavists conveniently ignore the numerous hymns in the Vedas to Indra, Agni, Varuna, Soma calling them all supreme etc, and prefer to just focus on less than a dozen hymns out of thousands to a minor Vedic god like Vishnu.
What the OP lacks, is what I have told him elsewhere before, is historical context. The Vedas are not a coherent and unified text authored by a single author or a single group of humans, it is composed by countless authors over thousands of years, most likely going back to the early Mehgarh phase of the Indus Valley civilisation. It documents the evolution of religious thought among the early Indian people. Like all primitive cultures the original Indian people worshiped many gods, each clan worshiping their own favorite god, so some worshiped Indra, some worshiped Agni, some Surya, some a combination. Again like all primitive cultures, they pleased their gods though sacrifices by offering food, animals, even occasional humans(a practice common among other early cultures like the Druids, Jews and Native Americans) As Indian society developed going from agrian Mehgarh phase to the urban phase of Harrapa, we see the refinement of religious thought and the reduction of the number of gods from dozens to just one, reflecting the development of organized society. Hence in the later hymns of the Vedas we find monotheistic, pantheistic and monistic thought appearing, albeit in a very rudimentary and unconsolidated form. Just as we find in the history of Judaism the transision from Elohim(gods plural) to one god. It is not until Vedanta that the concept of just one singular reality is consolidated, giving birth to something even beyond montheism, but monism: Brahman and Atman as both interchangeable concepts. In the same axial period, we find that other cultures in the world are also forming similar concepts such as the Zoroastrians, Greeks, Egyptians, Chinese. This is either because of historical cultural exchange between our ancient people or some kind of collective unconsciousness explanation, the simplest explanation is cultural exchange.
Vedanta is not the only articulation of Gnostic philosophy found in the ancient world, but is clearly is the most well developed articulation of it. The reason for this is not because of Indians being special, but because they had a climate of free philosophical thought which allowed the darsanas to come into existence, whereas their most closest counterpart the Greeks were not as free and would face persecution for going too against the grain, such as Socrates. However, in later modern Western philosophical thought we find very well developed ideas similar to Vedanta emerge because of a climate of free philosophical thought appears in the West in the age of enlightenment. Western philosophy thought has only just reached the mature phase of Vedanta philosophy in the 21s century, this is why the Indian philosophical tradition despite being thousands of years older reads like debates in contemporary philosophy and is very relevant even today in modern philosophy.
what is the point ?