If people think these Mohammedans are getting interest free loans, and paying principal only, they're wrong.
The way these things work is that an intermediary keeps the title of the house, and charges the Mohammedan the principal and RENT over and above the principal.
So, instead of paying interest, they pay "rent."
They are not getting a better deal than anyone else. When it's all said and done, it's probably a worse deal, but technically they are not paying any interest.
The intermediary is not working for free - it's definitely a worse deal. Also they can't take the interest deduction, so it's most definitely a worse deal. But they remain "pure"...