I'm pretty sure Peter Thiel is well informed about Bitcoin.
How can you be pretty sure?
It's a reasonable assumption given that A) Thiel is an intelligent, tech-focused person and B) his entire business and fortune was built on the online currency industry. For him to have no knowledge of Bitcoin would be, if nothing else, unprofessional.
An unreasonable assumption would be that he's never heard of Bitcoin, but if he did, he doesn't give a rat's ass about it.