To be fair, Eleizer, if the alien's brains were as sloppily put together as ours (and that seems likely), it should be entirely possible for them to develop sexual fetishes by having the part of their brain concerning sexual activity and eroticism getting miswired (and they almost certainly will have such emotions if they reproduce sexually, even if it expresses differently to that of humanity; a sexual organism with a sex drive will out-reproduce those without one).

From there, it seems entirely possible for the alien to develop a human fetish the same way it's possible for a human to develop an alien fetish, even if they do have a truly alien mind architecture.

Alternately, the stereotypical image of the "alien carrying off a helpless young woman" could just as easily be the result of the bias of the reporter who's taking the image. Which would you rather take a photo of, if you were a reporter on the scene of an alien pirate raid: an alien carrying off a bag of grain, an alien carrying off a toolbox, an alien carrying off some livestock, or an alien carrying off a helpless young woman?