The Sith are actually pretty liberal. They believe in the rule of the emperor and expect total loyalty to the government (Empire).
Considering the Sith, or at least Palpatine, were based on Richard Nixon, and the Rebels were based on the Vietcong, I’d contest that the Sith were liberal. At worst, they were neo-Conservatives. If anything, it’s the Old Republic and especially the Rebel Alliance that were liberal, since the latter was literally based on the Vietcong, a very left-wing group (and thanks to that, I no longer root for the Rebels), and the former was an overglorified United Nations, and arguably had far BIGGER government than the Empire (for instance, the Old Republic had four branches for intelligence. The Empire only has one). Again, just ask George Lucas, he can verify at least the bit about the Empire being America and the Rebels being Vietcong in great detail, Walter Murch as well.
Anyways, I would consider George Soros to be more comparable to Lord Voldemort than to Palpatine, to be honest. Palpatine was pretty open regarding who was in charge, namely himself (yes, he played both sides, but on the other hand, Sidious and Palpatine were one and the same, so yeah, still out in the open). Voldemort, on the other hand, did not make his running the ministry of magic apparent and ran it in the shadows, having a puppet leader installed (literally, in this case, as the Minister of Magic he made a plant for the Death Eaters was put under the Imperius Curse), and George Soros does not directly run affairs in America, but instead operated via proxies.