Why do muslims falsely preach that there is not a death penality for leaving islam?

No death penalty for leaving islam?? Really?? The prophet muhammad did kill a number of people who deserted Islam and so the punishment is Sunnah (actions and sayings of muhammad) and hence Shariah, Islamic Law. One whose name has been left to posterity was Abdullah ibn Saud, one of muhammad's scribes (muhammad was illiterate). Abdullah had come to the conclusion that muhammad himself, and not Allah, was the author of the Qur'an and left Islam. So muhammad killed him.