Causing bloodshed is unfortunately part of the human condition. It is not exclusive to Muslims. It so happens that we are living through a phase in history where most Muslim nations are coming out of a long period of colonial subjugation, and are still facing other forms of suppression by non-Muslim and Muslim powers. There is a profound imbalance in access to wealth, justice and knowledge. As a result, some Muslims are lashing out in desperation. Hence the perception that Muslims are fighting each other.
But if you put things in perspective, human beings though out history have been fighting each other. Some of the greatest genocides have been perpetrated by people who do not profess Islam. Think of the Mongol invasions, the conquest of the Americas, the Spanish inquisition, the Crusades, the Bolshevik revolution, the Chinese revolution, the two world wars (including the Holocaust), among many, many others. "Muslims fighting each other" are almost insignificant in comparison.
As human beings we are hardwired to fight and cause bloodshed. The Qur'an relates this conversation between God and the angels before humans were created:
When your Lord said to the angels, "Indeed, I will make upon the earth a successive authority (humans)." They said, "Will You place upon it one who causes corruption therein and sheds blood, while we declare Your praise and sanctify You?" Allah said, "Indeed, I know that which you do not know."
This, of course, is a commentary on the basic nature of humans. It does not exonerate individuals if they take a life unjustly. We do have free will, and will be held accountable for our actions.
Having said that, and as has been mentioned by
@Taimur Khurram, death (and other misfortunes) does not have the same effect on a Muslim as it has on most non-Muslims. The reasons are beyond the scope of this thread. But that is also the reason that depression, despair and suicide are less prevalent in Muslim societies.
