Just pointing out some weak arguments.
War is a continuation of politics by other means.
Murder is the unlawful, premeditated taking of another's life.
Killing during war is not murder. Since it's kill or be killed, there is really only one option, and when you're on the defensive there's absolutely nothing wrong with it. It does get a little muddy, as I'll explain in the following point.
Technically this is a lie, but it's a very ~nuanced~ point.
Prior to Stormblood, this was true. Every conflict with the Empire was started by them - I could argue the reasoning behind the Empire's aggression, but I've done so countless times and it's kind of irrelevant to the point - so opposing it was a matter of self-defense, not malice or hatred.
However, while the conflicts of Stormblood were kicked off by Ilberd, there was the option of sitting on it and doing nothing - after all, the Masks were behind the false flag operation, and the Eorzeans ran in trying to put a stop to it. However, while the operation was stopped and Shinryu contained, the damage was already done. The Empire had every reason to believe the Eorzeans had launched an offensive against it, and there were not (and still are not) any diplomatic channels to peacefully resolve the issue. Even if there were, though, it's unlikely the Empire would really care... a convenient excuse is still an excuse, and we know the Empire's goal is global domination. Not doing anything would condemn Eorzea to a grisly fate and, for the Warrior of Light, likely be suicide given the Empire equates Echo users with beastmen.
So Eorzea went on the offense against the Empire in Ala Mhigo since not doing so was far less prudent given the circumstances. The Doman insurrection was also an aggressive move, though like the Ala Mhigan resistance, the grievances driving it were also perfectly understandable.
... but to say that we've only ever acted defensively against the Empire is, technically, a lie. Eorzea launched a preemptive counter-offense; technically, this makes it the aggressor.
The latter point stands, though. Aside from the threat the Garleans present towards Eorzea, they seem largely apathetic towards the Empire's activities (hell, they left Ala Mhigo to rot for two decades and only did something because a madman left them no real choice) and would gladly leave it alone if it stopped threatening them.