If you own all of the endpoints, then it is indeed morally okay for you to do network-level filtering. The problem is that if we design network protocols so it'

If you own all of the endpoints, then it is indeed morally okay for you to do network-level filtering. The problem is that if we design network protocols so it's possible for you to do that, then it will also be possible for people to do network-level filtering that affects endpoints they don't own.