I doubt he used the word "rape", as there is no concept of rape in Islam. There is only haram and halal sex, which is in reference to the owner of a woman, not the consent of a woman.
Otherwise he is right, rape is allowed in Islam, see this hadith where Mo himself allows it:
Muslim, Book 008, Number 3371:
Abu Sirma said to Abu Sa'id al Khadri (Allah he pleased with him): 0 Abu Sa'id, did you hear Allah's Messenger (may peace be upon him) mentioning al-'azl? He said: Yes, and added: We went out with Allah's Messenger (may peace be upon him) on the expedition to the Bi'l-Mustaliq and took captive some excellent Arab women; and we desired them, for we were suffering from the absence of our wives, (but at the same time) we also desired ransom for them. So we decided to have sexual intercourse with them but by observing 'azl (Withdrawing the male sexual organ before emission of semen to avoid-conception). But we said: We are doing an act whereas Allah's Messenger is amongst us; why not ask him? So we asked Allah's Mes- senger (may peace be upon him), and he said: It does not matter if you do not do it, for every soul that is to be born up to the Day of Resurrection will be born.
or this one:
Sunnan Abu Dawud, Volume 2, Number 2150:
Abu Said al-Khudri said: "The apostle of Allah sent a military expedition to Awtas on the occasion of the battle of Hunain. They met their enemy and fought with them. They defeated them and took them captives. Some of the Companions of the apostle of Allah were reluctant to have intercourse with the female captives in the presence of their husbands who were unbelievers. So Allah, the Exalted, sent down the Quranic verse, "And all married women (are forbidden) unto you save those (captives) whom your right hands possess". That is to say, they are lawful for them when they complete their waiting period." [The Quran verse is 4:24].
See also this fatwa:
http://islam.tc/ask-imam/view.php?q=10896
In other words, just as legal possession of a fish that has been fished out of the water, makes it Halaal for human consumption without the initiation of a formal slaughtering process; similarly legal possession of a slave woman made her Halaal for the purpose of coition with her owner without the initiation of a formal marriage ceremony.
Also, Shia Islam allows anal sex, unlike Sunni Islam, at least in certain circumstances:
http://www.homa.org/index.php?option=com_content&view=article&id=56&Itemid=53