War with Germany in WWII wasjustified.

A really tough question. War has unintended consequences. Had ww1 not been fought then The atmosphere that brought Hitler to power wouldn't have existed and ww2 wouldn't have occurred. So was ww1 justified knowing it lead to the conditions to bring about ww2?
What about the American Revolutionary War? Canada is independent from England and I don't recall them fighting a war of independence. Would independence have come to America anyway? IDK.

War is economic stimulus. The top tier banks lend interest-laden money for war. These big banks love war.

Gotta kill people to make more people. Elbow room. Resources. The rest of it is words and posturing.

I havent studied WW1 much but it seems like it expanded because of the complicated treaties in Europe.I am not sure exactly what it was supposed to be against or why they called it the war to end all wars. WHen it comes to guys and their antics like Hitler it is harder to defend a pacifist stance to me though I am aware that as a country we have turned a blind eye to other genocides

Leaders that chose to go to war either want to conquer for land and resources or they want to force their lifestyle on others. The ones who suffer the most are the ones who have no say but are used (killed, damaged) to gain an advantage.

War is about power, control, and dominance. It is never justified.

Necessity is the mother of invention and desperate times call for desperate measures. Would progress, innovations, and inventions be as they are today? If wars never happened, most likely products of destruction would not have been invented, progress would have been slower and that may have been a good thing.

War is horrible and best avoided, but in some circumstances there may be no choice. What would have happened, for example, if the world had no gone to war to remove Hitler and the Nazis from power? Sanctions wouldn't have worked because they controlled most of Europe and had everything they needed to keep going; diplomacy wouldn't have worked because you can't reason with fascists. It would only have been a matter of time before all of Europe fell and millions more people would have died in the concentration camps. The Nazis weren't that far off developing a nuclear weapon at the time the Third Reich was brought to an end either; it might not have been long before the USA was attacked and, perhaps, also placed under Hitler's rule.

In that situation, war was almost certainly both justified and the only option.

what did they mean when they said WW1 changed the world?