That was the main thread in the discussion yesterday -- you're renting access to the provider's network and the endpoint connection hardware is a part of that. Even if you buy your own modem, the configuration is controlled by the ISP through the setup and the router (again, even if it's yours) will also be configured to allow some backdoor information for the ISP. I may be misremembering a bit of that.

I found the article, commentary is here: https://news.ycombinator.com/item?id=6997159