MONTERREY, Mexico (Reuters) -The armed men who kidnapped 32 migrants in northern Mexico over the weekend aimed to extort money from them and their families in the United States, Mexico's president said on Thursday, one day after the migrants were released from captivity. He said that the migrants, who were found on Wednesday, were abandoned by their kidnappers in a parking lot in a commercial center in the northern Mexican city of Reynosa in the state of Tamaulipas. "It was for the extortion of