This is a case of social contagion. Muslims get to rape with impunity in Europe. Kids from other cultures see this and befriend Muslims. They feel like they can get away with it to. If you do enforce the same morals for an entire country, moral rot sets in.

The same thing happened in America in the 1960s. Blacks let into the mainstream, but not expected to confirm to the mainstream values and morals. Whites who saw blacks getting a free pass said, "Why not me, too?" and thus the counter culture was born. Now American society has been reduced to a war of all against all. Does Austria want to follow suit?