The US isn't a capitalist society, and hasn't been even approximately for most of a century. Like most advanced Western countries, its a modern mixed economy, which features some elements of capitalism -- a system named by its nineteenth century socialist critics for its focus on the interest of the capital-holding class -- but also mixes in many elements of socialism specifically to mitigate the very problems with capitalism that were identified by the critics that named it. This model has -- in a process that, while it started earlier and never really ended, was focused in the early-to-mid-20th Century -- displaced capitalism as the dominant system of the advanced economies of the world.
I'm not sure why a socialist would be less appropriate a leader for a country with a modern mixed economy than a capitalist.
All of them were socialists who lead a capitalist society.
What makes you uncomfortable about them or their leadership?
