Snoweel said:
It's not so much that the Hyborian age is simply absurd as an even fictional postulation of Earth's prehistory* (though it surprises me that a construction worker like myself can have a better grasp of history than an academic like Howard) but rather that Hyboria's history (and thus culture development) is only slightly more internally consistent than a world like Greyhawk, which was built around the early, unconnected modules, and the many and varied locations described therein.
I have a few extra observations that may help put a few things in perspective.
Howard was not an "academic" in the sense that Tolkien was. Robert E. Howard sold his first pulp story at age 18, finished high school, and took some business courses. That was the extent of his formal education. He was, however, like Lovecraft, VERY widely read (However, a large portion of his reading was also works of fictional nature, so that may be where he got his portrayal of various ethnicities and historical groups). He was a deeply troubled individual, and committed suicide at age 31 shortly after the death of his mother. (It was either just before or just after, my recollection fails me). Rumor has it he considered suicide after the death of his dog at age 12!
This isn't a condemnation of Howard, but it may help shed some light on his life. I think the reason for the darkness and violence of his stories is that mentally he kind of "lived there" emotionally speaking, for the last part of his life.
(most of this info comes from the foreward of a book I own, a collection of Cthulhu short stories that Howard wrote using Lovecraft's universe.)
Also, it's interesting to note that Tolkien ALSO pulled the "earth's pre-history" idea with Middle Earth - look into some of the Tolkien critiques for his vision of the "history" and "future" of Middle Earth. So, yes, Middle Earth is a "Pre-history" of western Europe, according to some of the Tolkien sources.