They have lived in a country where women are covered from head to toe, so they are seeing for the first time : bare legs, lots of cleavage, pretty faces, long hair uncovered (blonde probably exciting, as never seen before).
They come from countries where women have no rights.
They come from countries where rape isn't a crime.
If they venture out late at night, in a City, they will have access to lots of women who are drunk, who will find it hard to fight off an attacker.
They can see from the news, that even if you get caught, and then convicted of rape, the sentence is non existent, or, even if you do go to jail, the jail is probably not that bad an option, as it'll be nicer than where they came from, they will get a roof over their head and 3 square meals a day for FREE.
AND
Many will be virgins, and those that aren't virgins haven't had sex for a VERY long time - they will be about as horny as it gets. Sexual urges and the raging horn, plus an erection in his pants, will override all common sense, in that moment.
I mean, how many times do men follow their dicks, without all the other stuff thrown in? We've seen it time, and time again, without all the extra factors listed above.