Stay away from words like always, everybody, never, etc. I can easily imagine one guy raping a pretty woman because of her prettiness, him want to have it, power etc. Another man would choose a not so pretty woman over a pretty one because the first has an aura of easy vulnerability which turns him on.
A saw a documentary about a killer who preyed on women. They showed him pictures of different women walking down the street and he could see the one who was most vulnerable, by the manner in which she walked. They played the video back in slow motion and explained the different types of walking....Just like a master musician can hear every discordant sound, these people study their victims and see in them things that you and I wouldn't even notice.
I would surmise that though there are commonalities between predators and they can be classed, there are also different motivations, etc.