Ohey I saw that in art history last semester. Some other teacher brought in a cast replica taken of the real thing, was pretty cool.
But yea, back in that day art wasn't how we see it now. It was moreso a form of language, or for record-keeping. And this thing dates wayyyy back, so nobody gave a shit about accurate representation, as you can still tell what it is.
It's like Egyptian art and it being entirely 2D- not to mention point perspective didn't exist at the time, but they still would have done it anyway to give you the whole story they were trying to present.