Darnus was able to see the future because he spoke to a Seer. While that may be a little extreme, Gaius wanted to convert Eorzea.
GAIUS DID NOTHING WRONG. He wanted to share his technology which means clean running water, daily showers as a concept, and toilet papers. Eorzea doesnt have toilet paper. Remember what next time decide to sneak a peak at Minfillia. Warrior of Light? More like Warrior of The Dark Ages. Thanks a lot, nerd.