The Pope is a proponent of what is termed, "LiberationTheology," which is a leftist slant on the teachings of Christ, promoting socialism in all its forms.
Its logical failing is that while socialism works in small, voluntary groups - like a convent or a monastery - it cannot work on a broad scale, where people who support it and people who loathe it are forced into the same oppressive paradigm of governance.
Further, Leftists like Pope Frank ignore political and practical realities when addressing many social issues, and mainly immigration. There is no God-given right for anyone to emigrate to a country in contravention of that country's laws. There is no moral principal that obliges any country to accept immigrants who "bring nothing to the table," who oppose the basic philosophies and mores of the country they wish to invade, or who will be a drain on the social safety net.
While many Muslims live peacefully and productively in the U.S., there can be no doubt that the basic tenets of Islam run counter to the U.S. Constitution. The Constitution prohibits religious interference with civil law, while the Koran demands that civil law be subject to religious law and religious officials. Muslims should the considered for immigration on the same basis as everyone else, but we have a right to ascertain whether each would-be immigrant is a threat to those living here legally already.
The Pope's opinion on the matter is of some academic interest, but carries no weight whatsoever, even with American Catholics. That is to say, if they are predisposed to think the same way, it makes no difference, and if they are predisposed to think the other way, they will pay no attention to Pope Frank...whose popularity among Real American Catholics is shall we say, not great.
Better if he would spend his time and energy getting more Italians to come to Mass; only about 5% of Italian "Catholic" adults attend Mass regularly, and that group is mainly those who are near death.