It's like this is the 21st century version of the San Francisco story where Yung refused to sell their house to the robber baron Cocker, leading Cocker to build an expensive three story tall fence around the house forcing Yung to move.
He could have banned the account on day 1, but he tweeted in defense of it. I don’t buy the theory that he had to wait to save face, he seems perfectly content to change his mind and make new rules on the spot without worrying about the backlash.
It seems more likely that he had idealistic reasons for buying the site and is becoming less idealistic as time goes on. Every worldview is flawed, you just don’t know it until you try to implement it. I think he’s moving past any initial altruistic aspirations and is now treating Twitter more like a tool that can be customized to achieve certain goals. I’m sure he thinks the goals are good for everyone, including himself, but from the outside it’s not mirroring the “public square”, “absolute free speech” mantras pre-acquisition.