[plausibility]

I think it's just because he had no illusions as to the good and bad uses it would bring. I've used Palantir Foundry heavily at work, and it is good for remotely viewing events and communicating mind-to-mind to executives with pretty dashboards. Definitely nicer optics than their Gotham platform used by USA law enforcement since e.g. it helps Airbus identify issues on their plane fleets before they occur.

Plus from talking to the Palantir engineers, the CEO and Thiel are both weirdo nerds, so it's fitting.