I am the original poster from the post linked in this article.

I know these as a fact that a comparable property in my city would cost me much more than what you're paying. All the while I'm getting payed less than half of my colleagues living in your area.

And there are many other costs that are comparable eg. electronics, vehicles and education.

All this is to say that location based pay is not about cost of living, its about getting away with paying as little as possible.