The idea that there is a “right side of history” is like the idea that you can have sex certain geometric figures: it’s more widely held than you’d expect, and it’s not entirely wrong in every possible way.
And that’s about all you can say for it.
History doesn’t have two sides, or ten sides, or sixteen sides. History has no shape any more than the traditional monotheistic God: there is no single shape which locks in, contains, something that much larger than what we can ordinarily reach or comprehend.
There IS a simple way to be on the “right side of history”, of course, and that’s to FORCE history into shapes with sharp, ugly lines and vast differentiation between the parts.
It helps if one side if obviously beatiful and perfect, and the other is visibly ugly, but you can be subtler than that if you want.
It’s not impossible to be on the right side of history. It would merely involve moving and manipulating so many lives that the people involved barely had a say in history, which seems a rather perverse way to tryh to build any kind of history.
But it’s pretty normal.
It’s mostly how history seems to be made, in fact.
So the next time someone tells me they’re on “the right side of history”, I’m going to tell them that I don’t care about fake geometry unless it involves smooching a triangle.