This claim only works if you stick very closely to the western post WW2 narrative that is neither accurate nor robust enough to withstand a few hours of research.

I should've said post-1945. That was imprecise. My bad. Economic sanctions are largely a post-1945 tool. Sure there are examples like stopping oil exports to Imperial Japan but sanctions as an economic regime where a large part of the world isolates you economically didn't really happen until the Cold War as the US remade the economic order post-1945. Since then we have a 100% failure rate for economic sanctions of enemies.

But let's discuss your examples.

Germany was obliterated, levelled. They supported their own war effort basically until the day the war ended. Deaths in the camps happened basically up until liberation. In some cases it was a few days before as the SS fled the Allies. I'm not sure total military defeat counts as being welcomed.

Japan? They were prepared to fight to the death. It's debated why Japan ultimately surrendered. The popular version is because of the atomic bombs. A likely more accurate reason is because the USSR entered the war. When exactly did they welcome us?

France was occupied by Germany so yes, they welcomed those who liberated them from their foreign occupiers. How does that relate to Iran?

South Korea depends on what you're referring to. First there was the Japanese occupation that ended with Japan's surrender in 1945. Again, like France, we removed their occupiers. But then we installed a military dicatatorship and started a war because communism. It's also worth noting that North Korea was wealtheir than South Korea until the 1970s. It took decades of military occupation (in the south) and economic sanctions to reverse that. Oh and South Korea is now facing total population collapse within 2-3 generations so there's that too.