Maimonides has no quarrel with the strict monotheism of Islam, but finds fault with the practical politics of Muslim regimes.
He also considered Islamic ethics and politics to be inferior to their Jewish counterparts.
God is not pleased by blood – and not acting reasonably is contrary to God's nature. Whoever would lead someone to faith needs the ability to speak well and to reason properly, without violence and threats...
To convince a reasonable soul, one does not need a strong arm, or weapons of any kind, or any other means of threatening a person with death.
They were called "Hagarenes" because they were "the descendants of the slave-girl Hagar".
As such, there have been several notable critics and skeptics of Islam that arose from within the Islamic world itself.
Islam's sensual descriptions of paradise led many Christians to conclude that Islam was not a spiritual religion, but a material one.
Although sensual pleasure was also present in early Christianity, as seen in the writings of Irenaeus, the doctrines of the former Manichaean Augustine of Hippo led to broad repudiation of bodily pleasure in both life and the afterlife.
He reasoned that the Sharia was incompatible with the principles of justice, and that this undercut the notion of Muhammad being the perfect man: "there is no proof that Muhammad attained perfection and the ability to perfect others as claimed."That is why, to this day we never see anyone converting to Islam unless in terror, or in quest of power, or to avoid heavy taxation, or to escape humiliation, or if taken prisoner, or because of infatuation with a Muslim woman, or for some similar reason.
Nor do we see a respected, wealthy, and pious non-Muslim well versed in both his faith and that of Islam, going over to the Islamic faith without some of the aforementioned or similar motives.