Oh, I'm well familiar with the Islamic restrictions pertaining to interfaith relationships and marriages. In fact, I was initially the first one in this thread to bring it up a few pages ago (I even discussed it with Ssainhu, who succinctly outlined the hypocrisy and inconsistency of such restrictions).
You see, 0ne-answer, one of the best ways I evaluate a socio-religious community's openness and compatibility with a pluralistic socio-cultural environment is by analyzing the rate of allowance of interfaith marriages, particularly that of female members marrying male non-members. And Islam, unfortunately, has a horrible track record in this regard. Not only is a conversion a requirement, Muslim females are often never allowed to marry non-Muslim males (especially if the non-Muslim males desire to retain their original religious identities).