The Central Powers were also assholes. Germany invaded neutral countries (one of the reasons the war kept escalating), there was the Armenian Genocide conducted by the Ottomans, and they were the first to use chemical weapons and mostly against civilians.

Of course, the Entente was in it for imperialism as they would divide the carcasses of their enemies between themselves. The US was no different. I can see how people could draw conclusions about involvement in WWI as justified, but those justifications go out the window once you look at what happened post-war. It becomes obvious the entire conflict was a meaningless slaughter all so bourgeois could eradicate what was left of the nobility, then take their place as the boot stepping on the proletariat.