You completely zoned out on the Garlean storyline then. Its a nationalist, isolated military country that despises its neighbors which it is perpetually at war with. Theres 24/7 propaganda blaring on their radios before the Final Days. Their leader was assassinated and their capital exploded, all of which was blamed on Eorzeans through propaganda. And now you stroll in with multiple armies and you think its weird that they don't trust your intentions? They think you're there to conquer, to get revenge. It doesn't matter if you claim to just want to give them food and aid. For all they know you are just waiting to get their guard down and be complacent so you can enslave them. The Garlean's concerns are completely realistic given the situation.