There is no reason or morality in Islam, and no shared premises that could act as a foundation for discusion.
"Nor is there the concept of Natural Law --that ethical code that any rational person, with faith or without, should be able to discern using reason alone. It is this code of ethics alone that religious believers can and should fight for in the public square. Islam, of course, rejects reason as a reliable source of ethics; all its dictates come from infallible Revelation, and they all make the same claim to authority.
Polygamy, marriage laws (including Muhammad's "excellent example" of marrying a nine-year-old), the subjugation of dhimmis--these are subjects of exegesis for Islamic scholars, not of dispute among philosophers. Because they do not believe in Natural Law, it is pretty much impossible to dispute with honest Muslims about politics or human rights; we literally share with them no premises.
As Robert Spencer pointed out in his debate with Peter Kreeft, whenever Muslims make generalized ethical statements that sound like they offer common ground, they almost always mean (whether or not they say), "for Muslims." Thus, "We believe in freedom of religion..." (for Muslims). We believe in social equality..." (for Muslims). Since all ethical discourse comes from Revelation, not reason, all rights pertain to believers. Everyone else exists merely upon sufferance."