Ah. So what they are saying is that their 500TB CSAM was removed but they recovered 400TB. They were using it to build hashes. Yeah I would not expect them to share that with the world. It would not surprise me if automation removed it because it is CSAM.
Perhaps they should store such things on hardened secured servers in NSA data-centers (yes, related) instead of Google servers unless the plan is to integrate the CSAM into Google. Otherwise generate the signatures on hardened infrastructure that Google employees do not have access to and then share the signatures with all the hosting providers. (Checksums, Microsoft PhotoDNA, etc...)
