There are nuclear weapons and then there is nuclear power. I think fear over nuclear weapons is weaponized to keep us dependent on fossil fuels. People weren't so worried about "world wars" prior to 1900 or so because they didn't have fossil fuels to drive/sail/fly around.

>People

Politicians/intellectuals have a (unifying) front on nuclear, voters care more about fossil vs solar

Mirrors the diverging reception of Abundance?

I’m a bit confused by your phrasing. Isn’t our world also plagued by constant wars fought with conventional weapons?

It is, but these are much smaller-scale. The border between France and Germany has seen full eighty years of peace, which that land probably did not see since the time German and French nations formed. It's hard to imagine a full-on war between two countries possessing nuclear weapons, because it would be suicidal for the attacking party, so e.g. India and Pakistan remain at peace.

Even a war at the scale of WWII every half-century is far better than a nuclear exchange.

MAD works until it doesn’t. It’s almost inevitable that some cretin will hit the shiny red button at some point.