Mohamed received his divine revelations telepathically from the Archangel Gabriel. But people don't understand the these transmissions can be biased and colored by the recipient's mind, especially if his mind is filled with certain existing beliefs and prejudices from his own culture.
In Mohamed's case, being born into a warring culture amid ongoing wars with the Meccans tainted his mind and distorted some of these revelations with dogma of violence. Until the Islam purges violence from its doctrines, the religion will not progress.
Having said that, despite Jesus' repeated proclamations of non-violence ('turn the other cheek'), the Catholic church still managed to pervert his teachings and engage in large scale violence like the Crusades, Inquisitions, witch hunts and pograms, all in the name of God. (Gallileo was jailed and Giordano Bruno executed for saying that the earth revolves around the sun.) Passages referring to reincarnation were expunged from the gospels to instill fear in the congregation of eternal damnation in hell and chain them to the Church & clergy.
If not for the scientific and industrial revolutions and the separation of church and state, Christianity would be stuck in the Middle Ages like Islam is today.