You jest, but ssh/git has a similar problem. The client tries every key it can if the config is naive enough. So, the server knows which cluster of public keys identify the same person. Github is said to do this kind of fingerprinting.

I don't think you understand.

Actually keeping screenshots would be expensive. They of course don't care what the content is. You care what the PGP content is.

They care about what you're watching, so in the dystopian future, they can tell a government that your bin of hashes are 90% banned content and you should be denaturalized because you're clearly a communist cross-dressing monkey from mars.

It's bizarre you think it's equal to knowing a PGP key. It's not, the point is the database of hashes are good enough to tell them things about you. They could do a lot of different malicious things with that knowledge, primarily because it's not anonymous information. They likely have GPS, so they know where you are at the same time, even not having GPS, they include wifi, and some have cellular chips.

If you think what we're talking about equates to PGP, you are seriously confused about how privacy works.