That's disgusting. I assure you that anyone who marries a child is not a true member of Islam, no matter how much they protest and claim that they are Muslim. Whoever that guy was who married a child was definitely evil and probably just trying to stain the good reputation of Muslims with his evil actions. He should absolutely not be recognized as the prophet Mohammad. Maybe he was just a different guy named Mohammad? Allah knows there are a lot Mohammads running around.

Anyway, that's clearly unacceptable and since Islam is virtuous and good, it would never condone that behavior.