They were saying it wasn't meant to be personally identifable. Not that it wasn't. And they're right, a large part of the foundations of the internet were built and designed for the past and what was happening in the past with no real idea of how it would all grow and we would continue to use these building blocks.

Email is a great example. We've patched things on top of it to try and fix the fundamental flaws but they're still there. An easy one is that you don't have to prove you own an email address to send an email that looks like it's from that sender. We added DKIM, DMARC, etc. But the flaw still fundamentally exists.

Understood, and I don't disagree with their idea of how it ought to be. But realistically, that ship has sailed. It's even coded into law now: an IP identifies a finite group of specific people. I wish that weren't the case, and I roll my eyes every time that comes up in a legal conversation, but we lost the argument.

As an aside, although I haven't seen any explicit language discussing this, I'd say that an IPv6 (even a random one thanks to privacy extensions) is exactly equal to an IPv4 address. My house has a static IPv6 prefix, so if you see an IP from that subnet, it's someone in my house, exactly as if our shared IPv4 address showed up in the logs. In my opinion, the host portion of the address is basically equivalent to a random port number for identification purposes.