Around 100 years of history isn't a big sample size when it comes to political/economic ideologies. Also, I would argue their are examples of it existing with non-evil dictators. I won't bother naming anyone specifically as it's easy to say 'but x did y' however I feel like that applies to a majority of world leaders under any system. There are certainly leaders of communist countries who did no-more evil than some of our recent democratically elected leaders in the west.