"people said the same thing when France opted out of NATO."

No they didn't.

They were shocked at how it was handled, but everyone recognized the fact that France wasn't at the core of NATO and wasn't the driving force behind NATO's founding (It was a US project). De Gaulle had long balked at the idea of taking orders from Americans, particularly when it cam to nuclear issues.

France was front and centre of the founding of the the European Coal and Steel Community, with both Schuman and Monnet working closely together. No other country had a more prominent role than France.

Huge difference