In other words: it doesn't matter your gateway logs shows that no one ever requested a file with a specific content hash, because should one eventually request that content hash from your gateway, they'd get the file in question.
Honestly, until reading the headline, it never occurred to me what now I realize is stupidly obvious: the promise of p2p content-hash-based distribution is that it's robust and censorship-resistant, as the targeted data isn't bound to specific places, but rather is automatically mirrored and made available across the entire network. The flip side of the data being accessible from any point in the network, however, is that... the data is accessible from any point in the network - meaning that every point individually is distributing everything that's in the entire network, and is potentially liable for it all.