The author is incorrect. While Signal Protocol is used to communicate an SRTP master secret and a session id, the clients still need to do an ICE handshake in order to establish communication with each other before the responder can even ring. It is very straightforward for SA to block that traffic, and it is established fact that they do.

It seems as if WhatsApp is short circuiting this frustrating series of timeouts to improve a flaky seeming UX. That strategy does negatively effect people on the internet who register for WhatsApp with Saudi VoIP numbers when they're in France, but it is a much clearer UX for almost everyone who is actually a Saudi WhatsApp user or calling actual Saudi users. What the author is demanding is a worse UX for the same outcome.

It sounds like there might be room for improvement, but I have a feeling that if WhatsApp were recording their users' locations in order to provide a more advanced location-aware version of the same strategy, people would not be very happy about that.