Did not America threaten to use nuclear warheads in Afghanistan? It literally went into Iraq after the made-up threat of nuclear weapons in Iraq.
I don't think the West ever spoke out against America when it waged all those wars. Oh it does now but now it has become political. The wars have been waged, cities have been destroyed, civilians are dead, and so these wars become unpopular. No one stood up to stop those wars and I bet no one will stand up again.
So no, Russia-Ukraine war is not different because Russian has nuclear warheads. It's wrong. It's bad. It's consequences will be horrifying. All true. But in this instance, nothing puts it apart from all the other wars.
There's a difference between being anti-war and being silent. Silence is acceptance. And the world remained silent when people were dying in all those war-stricken countries.
Just to put things into perspective: America went into Afghanistan and stayed there for 20 years. 20 years long invasion. How long in Iraq? How long in Vietnam? Now Russia opens a front against Ukraine and suddenly everyone thinks it's different. It's not. It's the same thing in a different country. Big oppressing small. Sending a message etc etc.