If they censor in this way then they are not a real internet service and should not call that (nor should they be given the enough IPv4 address ranges like ISPs

If they censor in this way then they are not a real internet service and should not call that (nor should they be given the enough IPv4 address ranges like ISPs; so, maybe they will run out if they are not a real ISP!) (unless perhaps you can get rid of the censorships by disabling NAT which you would freely be allowed to do, maybe). Real internet connect through proper protocol routing to the address based only on the packet header, and not the port number or payload (unless the packet is directed to the ISP's servers anyways), for the purpose only to routing to the correct destination and to receive the correct reply (if the payload is incorrect, they should send it anyways; that is not for the ISP to consider unless the packet is directed at their own servers) (however, if the header is incorrect (including specifying addresses that are impossible, but not only if they are merely censored), then they can block it; note I mean the IP header, and not the TCP or UDP header, which is at the other level than the routing, so they should not tamper with). (For example, if the packet specifies 127.0.0.1 as the source or destination address, then they are allowed to block it; and if you do such thing too much, they can even warn you to correct your computer.)