In episode 7, "The Backbone of the Night," Sagan describes the development of empiricism and the opposition it faced in society. Sagan also characterizes Plato and Socrates as proponents of elitism, secrecy, and slavery. Pythagoras wanted to keep knowledge and discovery secret from the general population. Sagan's argument is that Greek society ultimately supported Plato and Socrates rather than empiricists because the ideas of Plato justified the Greek slave system. How accurate is this depiction?
Ugh, it is awful. Sagan was an astronomer and a brilliant presenter, but when dealing with history he has a tendency to develop his narrative first, then see what he can use from the sources afterwards. The whole idea of Plato "killing" empiricism might actually be the most ridiculous for some really aggravatingly simple reasons:
If you want to find the roots of empiricism in the ancient world, you can find them in the pre-Socratics (which he calls the "Ionians"), but it is really Aristotle's baby. Aristotle, who was a student of Plato's.
Speaking of Aristotle, the most famous justification of slavery from antiquity came from him, not Plato. Plato doesn't really deal with slavery.
Also worth noting, the proto-scientists like Eratosthenes that Sagan so admired were all well after Plato. As a matter of fact, so were quite a few of the philosophers who grappled with the problem of slavery, such as the Stoics or Epicureans.
On a broader level, the idea of Socrates and Plato somehow replacing previous philosophers is really practically junior high level simplicity. Plato did not name the dialogues Parmenides and Protagoras because they weren't involved, and in the first book of Aristotle's Metaphysics he outlines the various schools of thought in Greece, of which Plato was one. The so-called "Pre-Socratics" continued to be read and discussed throughout antiquity.
So the narrative doesn't even stand up to the most basic of chronological scrutiny. It's almost like saying something like Adam Smith's writings forever superseded and extinguished Marxism. And on a broader scale, Plato really isn't a comforting reinforcement of social norms. He is a very complex and difficult writer who constantly challenges social and intellectual norms, and I can't really imagine him as the "safe" choice.