[njibhu]

A lot of devices (android/windows) simply don't support DHCPv6. And SLAAC's RA delegates the responsibility of the IP to the device itself, so doing something like DHCP snooping is simply not possible because the RA packet doesn't tell the switch which IP belongs to which device.

SLAAC-snooping protects against ARP poisonning, not against ARP table overflow.

[Avamander]

If it doesn't protect against ARP table overflow then that is again a missing feature in that software. Just like it's not IPv4's fault if there are no protections against someone sending a thousand DHCP requests and depleting the pool or filling some tables.