why apostasy In Islam Carries The Death Penalty ?

The punishment for apostasy from Islam is a controversial topic for Muslims living in the West and for ex-Muslims everywhere. That’s because Islam teaches that apostates are to be killed. We know from historic Islamic documents that during Muhammad's lifetime, and the lifetimes of the next four "Rightly Guided Caliphs", tens of thousands of Muslims left the faith of Islam and thousands were killed. On a large scale the Muslims made war on groups that chose to leave Islam and massacres of apostates occurred. On a smaller scale individual apostates were executed. This death sentence is in effect whether or not the apostasy occurred in or out of the Islamic state.

why must be killed ?