Attacking another nation in a war doesn't suddenly make every single member of that nation or army 'evil', though. Especially when the war is caused over a genuine conflict of interests. Yes, Garlemald is the aggressor - but we don't know the full extent of their reasoning and we do know that Eorzea is far from flawless itself.

How many of the Garlean soldiers slain during this war were just following orders, I wonder? How many were killed believing that their cause was righteous? How many of those killed during the assault upon Garlean bases were non-combatants or medics that simply wanted to protect their comrades and friends? Heck, there's a quest in Western Coerthas that shows that even the Dravanians - previously thought to be mindless drones at Nidhogg's command - kept mementos of their fallen in a manner similar to what our side did.

There's a precedent for conflicts in this setting to not be black or white, even if they initially seem that way at first glance. I'd say it's far, far more likely that Garlemald as a whole isn't all that bad - including the invading forces - than Garlemald as a whole being irredeemable. If we're lucky then the developers will choose to explore that more in-depth at some point in the future, especially when Garlean plot points start to gather more momentum.

As an aside, though? War isn't pretty - and it is by no means as simple as the 'aggressor' being the 'bad guys'. That's just something civilians are fed to make them feel better about sending loyal men and women to die on the battlefield and experience the horrors of war themselves. So I'm inclined to drop this particular discussion due to clearly viewing it in a much different light than most people here.