"captures 99% of child exploitation" The majority of bullet holes are in the wings, so those need armor; the majority of child exploitation is through Facebook, so they need access to the content of the messages. It's an assumption made on incomplete information. The engineers only saw bullet holes in the planes that returned. And law makers only have information about the criminals who get caught. At least that's my understanding of the analogy.

The wrong assumption is in BuzzFeed's reference to "99% of child exploitation." The letter, which they deserve credit for quoting in full, says that "more than 99% of the content Facebook takes action against – both for child sexual exploitation and terrorism – is identified by Facebook's safety systems" (which rely on Facebook being able to automatically analyse unencrypted messages), "rather than by reports from users" (which could still be submitted if Facebook implemented E2EE by default).

Assuming you discover child exploitation on Facebook, why would you report it to Facebook, rather than the police? The police can actually arrest people.

I don't think it is related but it is still interesting!