I heard a podcast one time where the guy was asking "Who was more evil, Alexander the Great or Hitler?" and his point was that, whatever crimes were committed, Hitler believed that he was doing good for the German people. There was an actual belief system, as horrifying as we find it. Alexander, on the other hand, appears to have tried to conquer most of the world for no other reason that his own personal glory, committing crimes on those he conquered that lacked only the industrial scale of the Nazis, such as massacring the male residents of any city that resisted him and selling the women and children into slavery.
And yet today, Hitler is considered the arch-villain of all time and Alexander is "the Great." Partly that's the result of the Romans, an aggressive people themselves, making Alexander their hero a few hundred years after his heyday. It makes you wonder what Hitler's image will be a thousand years from now.
Alexander’s policy of killing or enslaving the inhabitants of cities he conquered was pretty much standard practice in that period. It was done regularly by Greek cities against other Greek cities during the Peloponnesian War. However evil, it was not particularly associated with Alexander, except that he was better than that.
Kind of unrelated, but there is a Greek story, I think, to the effect that Alexander had a dream that (what he considered to be “a”) god appeared to him and told him that, if he spared a certain city when people came out to greet him wearing certain ceremonial dress and surrendered, that he (Alexander) would be permitted to conquer the known world.
Turns out the dress was the High Priest outfit for the Jewish Temple in Jerusalem, they, too, had been told in a dream to ride out undefended and surrender with the gates of the city open.
Anyway, depsite Israel nominally siding with earlier enemies, Alxander did, inexplictedly, decline to attack Jerusalem, accepted their peaceful surrender, and let the Jews go about their business as a satelite nation of his.
I’ve heard a Jewish version of the same story.