The reference "the world is not stupid" simply meant that a lot of countries around the globe are seeing this mess in Ukraine as an avoidable catastrophe. The vast majority of countries have condemned Putin's SMO, but they do not blame him exclusively for this disaster. That's one of the reasons why so many countries have decided to remain neutral in this conflict. Maybe the line you are refereeing to was not the best choice of words (I agree), but the meaning is there, nevertheless.
Former US Secretary of State Henry Kissinger told the Wall Street Journal
"We are at the edge of war with Russia and China on issues which we partly created..."
