Huh? It's a widely recognised proverb, you might as well say that "What's sauce for the goose is sauce for the gander" is without much meaning. You could insist it's wrong if you like, or that it somehow doesn't apply but meaning is its whole thing.
You claim that "de oppresso liber" doesn't mean anything? Seems to me that it's meaning was pretty clear. Actually in this context I'd say there are two distinct meanings, both the "Regime change" bullshit from the start of this war and boots on the ground for a US combat unit. Seems like a poor comeback to any "War is bad" rhetoric because in my experience all such rhetoric sort of builds in a just cause assumption and that's really all you'd be going for with this phrase.
But then you say it's not a discussion, nobody said anything about it being a discussion.