Humanity has tried to be reasonable with Mutants in the past, but the acts of Mutants blinded by their "superiority" (like Magneto) has caused too much damage in human society. Many humans have died at the hands of the Mutants. Some of them might deserve it, but many others were just innocent individuals trapped in the crossfire. Now, the Mutants dare to resurrect while the innocent humans they killed in the past remain dead. That's not something they are going to tolerate.