Sauron is like the archetypal evil overlord. He's got massive armies of orcs. He has a headquarters made of volcanoes. And, he did... you know, he did all of those... things. And... And what exactly? Do tell me, because throughout the entire 2000-hour run of the Lord Of The Rings trilogy, I couldn't find a single reason why everyone demonized Sauron like he was a Obama at a Tea Party rally.

Well, he'll murder and enslave the world, plus he orchestrated the fall of the greatest kingdom of men from within killing cities worth of people and causing a lot more to drown.
He was also underling to the biggest bad of the world