You've been brainwashed by mainstream schooling

During 2007, Peruvian investigators found literally dozens of Caucasian mummies in a vaulted tomb buried 82 feet beneath the forest floor of the Amazon jungle. These belonged to a pre-Inca race known as the Chacha­poyas, or “Cloud People.” Their discovery complimented 16th century Spanish reports of “strange, white Indians” with beards in the same region.

http://www.renegadetribune.com/legacy-fallen-race/

There is widespread evidence of an Aryan presence in ancient Egypt. As author Mary Sutherland has pointed out, the mummy of the wife of King Tutankhamun had auburn hair. In addition, an ancient mummy with red hair, red mustache and beard was found buried within the pyramids at Saqqara. Moreover, the crocodile-caverns of Aboutfaida possessed a number of red-haired mummies. The book History of the Egyptian Mummies mentions a primordial corpse with reddish-brown hair. The mummy of Thutmose II has light chesnut-colored hair. Evidence of a Gaulish and Saxon presence has also been revealed by Professor Vacher de Lapouge. According to de Lapouge, a blond mummy was found at Al Amrah, the displayed skull measurements indicative of the White race. Blond mummies have been found at Silsileh as well.

During Pre-Dynastic and Old Kingdom times, Egypt was primarily a Caucasian society. The DNA of tested mummies reveals that even today’s own chiefly Semitic and Negroid populations bear traces of that lost European bloodline. In The Children of Ra, author Arthur Kemp noted a DNA study conducted by G. Lucotte and published in the American Journal of Physical Anthropology in April 2003 proved Egypt’s mixed racial heritage. But continued research has proven that, during past epochs, Egypt had three primary waves of Europoid inhabitants. During Pre-Dynastic times came members of a pre-Aryan or old European population from Eastern Europe and the Mediterranean. Nordic invaders during the Old Kingdom also arrived. And continued waves of Indo-European tribes throughout the Middle and Early New Kingdoms also made it to Egypt.

King Tut’s racial profile is decidedly Western European in origin, and the further you trace back through Egyptian origins the more homogenous and advanced the Caucasian population.

https://youtu.be/FEM-80qPJHo

You say "prevailing" but what you meant was "politically correct"

Light hair color is only found in northern latitudes;

Well, no. Muhammad had red hair, as the arabs emulate. There are Africans endemic to Africa who are white with blue eyes. The Inu of Japan. Ghengis Khan was also white. The early depictions of buddha all show him with blue eyes, extremely rare among the east asian haplogroup. I had a recent post in which is claimed the Vedas had to be written in the arctic.