Examples? Typically it only happens if some strong leader portrays another group as the enemy and manages to build up wide support. Manufacturing fear.

How about we take as a first one: do you seriously think WWII happened because Hitler portrayed the Jews as the enemy ? Do you think Iraq happened (first time OR second time) because Bush (first one, then the other) portrayed Iraqi's as terrorists ?Or let's take non-western conflicts. Say, Iran-Iraq war. Who demonized who exactly (as a cause of war) ? Do you think the Falklands war was about demonized Argentinians ?

I'm not trying to belittle or avoid the fact that people were demonized during these conflicts, in some cases with very unpleasant consequences. However, that had little to do with the conflicts themselves.

You think the people didn't feel the need for a strong leader because of a threat? Their economy was crap, and Hitler have them a scapegoat and scared them by talking about how dangerous they were and the need to become pure, etc...

Iraq for invaded because oil most certainly, using the fear of WMDs as the excuse.

You're also conflating the original source of each conflict with the reason for WHY the large masses joined in and took sides, the reason for why the conflicts COULD become large and dangerous.

In other words:

conflict one: economy was down the toilet, was attempt to fix it

conflict two: economy was bad, was attempt to fix that

My point was that conflicts happen (and grow) because the economy turns down, not because some people get demonized. That's a propaganda tool at best.

Not every poor country has gone to war. Propaganda is typically what makes people do so by amplifying fear and doubt and giving them The One Solution™.

Propaganda is a tool to start a war. It has nothing to do with the reason to start a war.