Obviously the native groups were very different then anglos but it's silly to speak about natives as some homogeneous group.

They're closer to each other, than say actual Asians or Blacks.

And Human sacrifices were found all over the continent. I have no idea why you think [the rest of] North America would be exempt.

https://en.wikipedia.org/wiki/Human_sacrifice#North_America

The peoples of the Southeastern United States known as the Mississippian culture (800 to 1600 CE) have been suggested to have practiced human sacrifice, because some artifacts have been interpreted as depicting such acts.[92] Mound 72 at Cahokia (the largest Mississippian site), located near modern St. Louis, Missouri, was found to have numerous pits filled with mass burials thought to have been retainer sacrifices. One of several similar pit burials had the remains of 53 young women who had been strangled and neatly arranged in two layers. Another pit held 39 men, women and children who showed signs of dying a violent death before being unceremoniously dumped into the pit. Several bodies showed signs of not having been fully dead when buried and of having tried to claw their way to the surface. On top of these people another group had been neatly arranged on litters made of cedar poles and cane matting. Another group of four individuals found in the mound were interred on a low platform, with their arms interlocked. They had had their heads and hands removed. The most spectacular burial at the mound is the "Birdman burial". This was the burial of a tall man in his 40s, now thought to have been an important early Cahokian ruler. He was buried on an elevated platform covered by a bed of more than 20,000 marine-shell disc beads arranged in the shape of a falcon,[93] with the bird's head appearing beneath and beside the man's head, and its wings and tail beneath his arms and legs. Below the birdman was another man, buried facing downward. Surrounding the birdman were several other retainers and groups of elaborate grave goods.[94][95] A ritual sacrifice of retainers and commoners upon the death of an elite personage is also attested in the historical record among the last remaining fully Mississippian culture, the Natchez. Upon the death of "Tattooed Serpent" in 1725, the war chief and younger brother of the "Great Sun" or Chief of the Natchez; two of his wives, one of his sisters (nicknamed La Glorieuse by the French), his first warrior, his doctor, his head servant and the servant's wife, his nurse, and a craftsman of war clubs all chose to die and be interred with him, as well as several old women and an infant who was strangled by his parents.[96] Great honor was associated with such a sacrifice, and their kin were held in high esteem.[97] After a funeral procession with the chief's body carried on a litter made of cane matting and cedar poles ended at the temple (which was located on top of a low platform mound), the retainers, with their faces painted red and drugged with large doses of nicotine, were ritually strangled. Tattooed Serpent was then buried in a trench inside the temple floor and the retainers were buried in other locations atop the mound surrounding the temple. After a few months' time the bodies were dis-interred and their defleshed bones were stored as bundle burials in the temple.[96] The Pawnee practiced an annual Morning Star Ceremony, which included the sacrifice of a young girl. Though the ritual continued, the sacrifice was discontinued in the 19th century.[98]

Republicans might lack historical nuance but as you've been told a hundred times already the alt right is not a conservative or republican group. It's a third position.

It doesn't stand to reason being alt-right/third position doesn't have its own nuances. Even when it comes to history, I would argue all sides of the political spectrum pick and choose which side they prefer to focus on.