I also believe they are idol worshipers with how much they twist the character of Hashem. How can one say that's the same G-d?
There also was a book I read onetime basically outlined how half of the Qur'an was written in the name of "Al-rachman" well later it changed in "Allah" there were two groups at that time who worshiped deities under these names. Islam was originally a polytheist religion that was redacted into a monotheist religion. The RamBam most likely did not realize this because he did not have access to the pagan sources of Islam that we have today.
The black pagan Ka'bah is one of the largest pagan idols in existence. Anybody who thinks Muslims are not idol worshippers or idolatorous really has their head up their behinds and knows little about Islam and its large variety of pagan practices. Muslims may have incorporated and adopted some Torah principles, but only to intermix them with their own heinous pagan mythology and ideologies. The pagan moon god al-iLah (Allah) is an ancient Arabian god who Mohammad help promote and was widely honored and venerated among various Arab tribes.
According to Arabian mythology and in some ways backed up by verses of Qur'an, that their pagan moon god of war actually dwells within the confines of the Ka'bah and the Ka'bah is a representation of their god in the physical form. The Ka'bah predates Islam as a pagan artifact of worship, although post-dates the life of Avraham, whom Mohammad falsely claimed built the Ka'bah.
This pagan idol is so revered that all Muslims around the world face the very direction of this mega-idol during their prayers. People seem to overlook the importance of this pagan relic, which they falsely claimed Avraham built. Also, the people do not realize the demands of a "True" Muslim to perform the Hajj where they will travel from the ends of the Earth to worship this black stone that houses the spirit or presence of their moon god.
Here is a picture of one of the largest idols in the world and is attributed to the Muslim faith: