From your point of view.

From their point of view, they are fighting against a dictator(true) in order to create a regime most of the people there want(a theocracy).

While doing so they oppress other people, like the communist did in the Spanish civil war.

Or put more simply, they fight for what they think is right, like volunteers did on both sides of the Spanish war.

Fighting for collectivism also seems like the opposite of fighting oppression, that's the nature of utopian and apocalyptic movements.

That's one of the most complicated situations that's ever been. I doubt anyone can at least admit they're just doing it to get bloody.