In that analogy, the /64 is their specific apartment, not the whole building. That is, they wouldn't get banned for something their neighbor did, because their neighbor would be in a separate /64.
That is, the whole /64 is equivalent to the single IPv4 address they have in their home router, not to the CGNAT which combines several home routers into a single IPv4 address.
That is, the whole /64 is equivalent to the single IPv4 address they have in their home router, not to the CGNAT which combines several home routers into a single IPv4 address.