Because I've been to the Sahara desert and it's the most remote place I've ever been. I experienced the gaps in coverage first hand.
There are equivalent places in central Australia, but even though I grew up here I haven't been more than a few hours drive away from the coasts.
I haven't been to North America. Russia didn't cross my mind, but I haven't been there either.
This isn't to say I don't have warped perspectives or prejudices about Africa. I didn't realize the population density is that high in the south, where I haven't been.
Western media only discusses African countries when things go wrong. The only people I know from there are three white families who left South Africa. If you asked me to draw a map of the countries it would be my worst continent.
The original post though really was just based on my personal experience with remoteness.