Muslim silence on anti-Christian persecution

Why do we as Muslims often stay silent when Christians in Muslim countries are subjected to attacks and persecution?

I say this in light of the disgusting murder of the Chaldean Archbishop Paulos Faraj Rahho of Mosul, Iraq last week. Iraqi Muslims rightfully condemned this disgusting act, but where were the indignant condemnations and outrage by Muslims in the West? God knows we tend to cry bloody murder when Muslims are being persecuted by tyrants (unless they are Islamic, cue the silence of the Taliban for example), yet what about the minorities in Muslim lands? Is their blood less worthy than others? Do Muslims apparently get a free pass to persecute and make life hell for Christians and others in Muslim countries?

Why is it so difficult for Muslims to bring light of wrongdoings like this? We all know the Prophet (saw) would not endorse the harm of minorities so what gives these Muslims the right to do so?

If we are going to bring up the faults of non-Muslim tyrants oppressing our brothers and sisters, then we must by that same token speak out when non-Muslims are attacked and murdered by Muslim extremists. The silence of Archbishop Rahho is extremely unacceptable.