The author is not claiming that companies are paying location-based rates in order to avoid social issues. Instead, it is argued that location-based pay happens to be in society's interests as well.

The author explicitly acknowledges that companies are minimizing costs wherever they can. This includes paying as little as possible for sufficiently qualified employees. The minimum salary these workers will accept varies depending on where they live. And if paying as little as possible involves paying different amounts of money to workers in different regions, then companies will definitely enact location-based rates. This is the argument made in the article.

So it seems that you and the author agree about why location-based pay is becoming prevalent. Next time, try reading the article more carefully before writing a convoluted, backward-looking response.