NAT isn't technically a security feature. And collusion isn't technically a crime. However, collusion has over a dozen different crimes associated with it. And all of THOSE crimes ARE illegal. Quit playing the semantics game, as an American I'm well aware of this game and am tired of it.
IPv4 NAT forces you to use your router, which in turn forces you to use your router's firewall. And if something breaks, it fails safely and blocks all Internet traffic until you fix it. That is a security feature, and one that the industry has used as a crutch for a long time. Home users doubly so.