Why is ISIS antagonizing potential allies?

[vinceasneed]

It seems as if ISIS could have fostered followers if they were more kind to nations that have a majority Muslim population. Killing the Christians in Egypt did not win over many friends there. The harming of Jordanian pilot also did not. If they truly want to engage in war, they might not need friends, but they surely don't need enemies. I wonder why they have chosen to anger people in their own religious sphere.