ORAN, Algeria — For a few years now, families of migrants from sub-Saharan Africa have been gathering at major street crossings in the large cities of northern Algeria. They come to beg for alms, wearing grotesque outfits: oversize veils for the women, even little girls; cotton djellabas for the men; prayer beads ostentatiously displayed. They say “Allah” too readily and misquote verses from the Koran.

Many black migrants, including those who are not Muslim, are deploying symbols of Islam to appeal to Algerians’ sense of charity. Why? Because poverty helps decode culture better than reflection does, and migrants, lacking shelter and food, are quick to realize that in Algeria there often is no empathy between human beings, only empathy between people of the same religion.

Another example: In October a Cameroonian woman was gang-raped in Oran by a group of men that threatened her with a dog. When she tried to file a complaint with the authorities, she was rejected on two main grounds: She had no papers, and she wasn’t a Muslim.

The Marie-Simone case became a cause célèbre, and the victim, with the support of some Algerians, eventually obtained justice. But it remains an exception.