1. arent "true sith" the thing revan found out about and was trying to stop from taking over the galaxy when he disapeared?
The vague "true Sith" that Darth Revan supposedly went off to fight is likely another attempt at the incredibly incompetent Drew Karapshyn to further butcher the cosmos with his unbelievable Gary-Stu of a character; meanwhile, in terms of in-universe canon, there is a difference between the Sith Order and the primitive species that shares the same name. Emperor Palpatine and his apprentices were true Dark Lords of the Sith -- legitimate in both name and heritage -- the ancient Sith spirits of Korriban having recognized them as such (specifically in Dark Empire).
2. I wouldnt exactly call the empire chaos. It actually was pretty good harmony. all those troopers working together for a common goal... I mean, there is such a thing as "evil" harmony... but george lucas's word goes above all so....
Restoring balance to the Force does not equate to "removing chaos" on a galactic scale, but rather on a Force-related scale. Sith upset the balance; they are Force-using abominations that quite frankly only exist to ruin peace and prosperity. Palpatine, manifestation of all this, was the true factor that made the Force turn to absolute shit for the Republic and the Jedi, thus balance was restored when Anakin Skywalker killed him at the Battle of Endor.
This is EU so they do count and technically with that logic I could say I hate kotor so Revan is not real You have understand the difference between GL's star wars and the star wars he authorizes aka the EU.
You are twisting Ushgarak's words. As an individual, you are at free liberty to believe whatever you want, however you want to. For the purposes of a debate, however, you can't blindly ignore canon on a whim.