As such, while the Mercator projection makes total sense for a map of northern Europe or the Caribbean, it makes absolutely no sense as a map of the entire world.
Keep in mind: that's 500 years ago, not 50 years ago. There's no question that we have better tools today but the question was why the mercator projection was so successful it became the default. I think "it was super useful at the time because it made navigation easy, reliable, and available to everyone, at any any weather" is a much more compelling explanation than "the would-be colonizers spread it because their home-countries were enlarged and they liked that and used it to oppress the equatorial countries".
With a compass, a sextant, a clock, and geometric calculations to get the intermediate points you'll then use a straight course to rally these point. The Mercator projection just inverse the order of the calculations (going from the intermediate points to course is straightforward as you just go in straight line over the Mercator projection), but deriving the said points requires calculations. If you have a globe, it's the other way around.
> is a much more compelling explanation than "the would-be colonizers spread it because their home-countries were enlarged and they liked that and used it to oppress the equatorial countries".
This is a strawman though, nobody serious would claim it has been designed for that reason. The fact is that it distorted the view of peoples in a way that aligned situ colonists propaganda at home. But those claims aren't at all equivalent.