... Now, I'm sure that there's plenty of the alpha and beta quadrants that's unexplored, why not avoid the gamma quadrant altogether and avert hostilities? ....
I think you mis-remember (though correct me if I do). War was thrust upon the Federation and the Alpha quadrant. As the result of a stable wormhole the Gamma and Alpha quads became within reach of one another and it was the Changelings who, out of fear, ordered first strikes and started the war.
I am generally against unilateralism as either valid policy or explaination. It's on par with blaming the victim for being raped.