You are wrong about your take on ancient greek history. Even the homosexual advocates today admit that there were no more homosexuals then as there are now.
It was NEVER normal then. The claims you state are just a propaganda developed by homoadvocates in the ivory towers over the course of the last 50 or so years.
Stone went to Greece to do research for this movie almost two years ago. He left after he did not hear what he wanted to hear and refused any assistance of historians and museum curators. (this is per the Greek Satelite TV's)
Per a review posted here, BTW, Stone's ending is supposed to be a statement against GWBush.
It was with great relief, even joy, that the top level guys in Greece saw Alexander off to conquer the world ~ at least he wasn't hanging around Greece bothering people anymore.
Modern Greeks want to think of Alexander as one of their own.
That doesn't make him straight, of course, but it also doesn't make him homosexual.