You’re looking at a map of undersea cables. You can’t see the terrestrial cables that connects to one or more of those locations. They are not an isolated “intranet” but connected to the internet.

Why ask if you won’t accept the answer?

I found this https://krg.ca/en-CA/assets/Council/2024/May/EAUFON.pdf which includes the terrestrial uplinks that do in fact exist.

Wireless has really limited range at high speeds. It needs to be high frequency to handle high speeds and high frequency is interrupted by mist, to say nothing of snow or rain, and high frequency also must be line of sight and simply doesn’t cover much distance. They would need to put up a tower roughly 1/4 as often as a wire carrying pole for much less reliability and much less capacity. Wireless is almost never the correct answer to a fixed connection.

It connects to those cables you saw. Then to the wider internet.

Wireless is hilariously power inefficient. You'd need massive cell towers everywhere with unlimited data, that are still connected to cables at the tower.

At a certain point its cheaper to lay a smaller power cable, and an internet cable, than a massive power cable to do point to point wireless.

There is a road going up there, and as another user pointed out there are overland cables connecting it to the rest of the system.