You can't say the same about the Sith! The Alliance were traitors! For the stability of the Galaxy, I declare the Sith Galactic Empire! The Empire brought peace, order, and security to the Galaxy! The Death Star's real purpose was to beat up the Vong! The Emperor was benevolent! He used his power to mantain order! The Jedi are traitors! They brainwashed children and turned them against the Sith, against the true keepers of order and balance! Look at how many innocents died by the hands of the Jedi.
Only powerful individuals are able to defeat this frightining threat. And it's clear the United Galactic Republic can't fight them off.
He was trying to protect the Galaxy against the evil Yhuuzan-Vong! He knew they would show up one day.