The Mercator projection is essential in practical navigation. Any projection from a spherical body such as a globe to a two dimension chart will result in distortions such as areas.
However, the Mercator projection has one feature that none of the other projections have and the reason that it has been used by navigators at sea for hundreds of years.
The feature is that say one inch equals ten miles at the middle of the vertical axis. Then everywhere else on the chart, one inch equals ten miles. One can plot courses, distances etc without changing the length of ten miles.
The Mercator projection has nothing to do with racism, colonialism, fascism, Trumpism, etc. but rather the safety for all ships at sea.
That’s basically what the article says. The Mercator is good for navigation and not much else. There’s no reason for that to be the “default” world map, something more accurate would be good, especially used in school texts.