I only raise the issue because I happen to know that China is involved in large-scale automated internet filtering and that in order to operate, companies are r

I only raise the issue because I happen to know that China is involved in large-scale automated internet filtering and that in order to operate, companies are required to implement those filters. And the fact of the matter is, many many firewalls ARE used for content filtering. For example, many workplaces block common time-waster sites. Home wifi routers can be easily configured to filter adult content. Universities block file-sharing. ISPs do bandwidth shaping. etc. etc.