@b9AcE yes, i agree, and this reminds me of windows 95, that had no firewall at the OS level, and it was the period of phone line modem connections, so you had everything open, and there was an SMB share setup by default by w95 on your storage; so, great mess :D
Anyway, that's how ipv6 works, so i guess the first responsibility to implement a firewall on both ipv4 (because it happens to use it not behind a router) and ipv6 is on the OS producers (be it the OS of a lightbulb, or of a pc, etc.).