Your classroom should’ve also had a globe.

And what makes you think it didn't? I was talking about books when I said - had Equal earth projection.

and because students aren’t retarded, you can simply explain to them the scale issue of Mercator

I'm surprised they're hiring 13 Yr olds as educators. You do realise that you can do the same with Equal Earth right? Explain it's advantages and disadvantages, point to a globe and move on.

Mercator is awesome because you can actually see all the detail in Europe

I don't live in Europe. From my perspective, details of Europe are not important.

which is supremely useful when teaching the world wars.

Those can be taught better with separate maps, sounds crazy right?

Our World History book has multiple enlarged maps of Europe, Japan, US, Russia, Vietnam. None of them were Mercator. Teachers also used interactive 3D maps. All of them rendered Mercator useless.