He pushed facebook to optimize for engagement, and used the tools facebook developed like every other propagandist.

Honestly, that's fine. The Obama campaign was lauded for similar social advertising, and had a direct relationship with facebook. That's how political campaigning works.

The converse is billionaires advocating for information control, and pushing to see that only those they endorse have a platform. So fat as I'm aware, Thiel hasn't done that. My position on him would change significantly if he had.