The Islamic world’s reaction to the ISIS persecution of non-Muslims is decidedly mixed.
This sentence from the link sums the situation up nicely:
At the same time that Islamic religious leaders are mostly silent on the genocide, Islamic political leaders have spoken out.
It appears that Islamic political leaders have generally been forthright in condemning ISIS’s actions, something that we should take heart from. Islam’s religious leaders however have taken a more partisan stand, worrying that ISIS’s actions might harm Islam and thus condemning it for that reason. That Christians and other non-Muslims might be murdered however does not seem to be a concern for these Islamic religious leaders.