Ah, a piece from the SoaSE: Storyline, huh? This ought to take a while: a-HEM!:
Living under said "strict, moral code" has turned our empire into perfectionists, and we are too self conscious and so we cannot accept that these "sinners" could possible have anything to do with what we want our descendants to see us as, so we eliminate them simply because they are too different.
Now, for the war part, the simple, obvious answer that the TEC is too stubborn and proud to do is diplomatic conferences, and therefore, peace. No war is just fought to be fought, everyone has a resolve, so we could find out what the Vasari's resolve is, and make peace with them. The Advent would be more difficult, but by offering them resources, their ancient homeworld, and a home in the new "World", we could easily stop the senseless bloodshed, and build a new "World" together, out of the one we destroyed.
Anything else, Mr. Enquirer (I only have 10 minutes left, so please make it fast)
Koda0 (^)
EDIT\\ Hmm.. touche Ryat, I'll have to look into leaving the basement for a while and getting this book. (lols)