Why is it wrong? You don't seem to be engaging the parent's point at all, which is that IPv6 addresses are a more specific identifier than current IPv4 addresse

Why is it wrong? You don't seem to be engaging the parent's point at all, which is that IPv6 addresses are a more specific identifier than current IPv4 addresses. The existence of link-local addressing has no bearing on that argument, because those addresses are non-routable by definition. Nor does stateful firewalling prevent your unique device address from being broadcast over the Internet, you'd need 6-to-6 NAT to achieve that.