not really keeping up on discussion, but from what I've read, both sides are kind of at fault for the conflict, as soon as the X-men find out that the cloud is about to infect everyone, they jump into action, not really giving the Inhumans a chance to do anything about the news before they're attacked. The X-Men could have gone to the Inhumans and requested help getting off world to someplace safe until a cure could be made or a new source of terrigen could be found. The Inhumans have been helping already moving Mutants out of the cloud's way. so I'm they would help. alternately, the Inhuman's could give up that part of culture and look for a new source of terrigen, which seems to take some super science to make more if the solicits are to be believed.
They could have framed it better and pointed out the ways to avoid conflict, which I think would have given the conflict a more dramatic theme about how two groups won't make a sacrifice for the other and favor their own propogation. could actually be quite relevant to the events happening today.