User blog comment:FairyRaven/Fairy Tail Chapter 448: Fight the Power! Review and Commentary/@comment-24102956-20150817075229/@comment-7418318-20150817093122

Actually Alvarez is at fault.

It seemed to me as if the island with the Star Mangos used to be independant and the Alvarez conquered it, so FT going there can't be seen as much of a crime... or at least a far lesser one than this unprovoked invasion and subsequent destruction of the island.

And on the main land too, Alvarez were first in their aggression. Zeref tried to (intentionally!) kill Makarov after all. Then FT tried to retreat, but again people from Alvarez tried to kill them. Not capture, but outright kill.

On top of that it's debatable whether Makarov really was a guest, or a well treated hostage/prisoner.

So from moral, legal and political sides Alvarez is "more guilty" than Fairy Tail.