The discussion here isn’t about whether the lives of remote people would be upended, but whether those countries would help to rebuild the ones hit by the war, the way devastated cities were rebuilt after WWII.
"How is anyone supposed to take that seriously? Is that how Cologne, Dresden, Würzburg and Pforzheim, or Hiroshima and Nagasaki looked a decade after they had been destroyed in Allied bombing raids? The truth is that even after infrastructure gets bombed back to the Middle Ages, life remains surprisingly normal, and people quickly rebuild."
The nukes that would fall today are a few orders of magnitude bigger than those that fell in Japan, and there would be many orders of magnitude more of them, and close together.
The world has never seen destruction and fallout that is even remotely comparable to what we’d get.