User blog comment:Godisme/Magical Barrier Particles/@comment-24112129-20131031162918/@comment-7418318-20131031165645

But that isn't the plot. It's just part of it.

Besides, Fairy Tail would have gone to war with them either way, since Tartaros already made a declaration of war agains the magic world by taking out the council. This is just a little extra motivation, rather than the singular reason for the war as it was in the Phantom Lord arc.