Your observation is correct. The reasoning is you can't get people to fight in a war or civil war or invasion by telling them "you're just like the other guys although your leaders doesn't like our leaders" Its easy to get them to fight if you can propagandize them into thinking the other guys have the wrong religious beliefs, they hate civilization, they oppose your lifestyle, they're deplorables, etc, then they'll fight.

This is why (small L) libertarianism and political centrism is hated by all groups of all opinions who are in power; you can't get people to kill for your profit using the rhetoric of "you have a nice life over there while I have a nice life over here".