On the eating issue, I think most people, at least in today's society, would have a problem with eating Kilrathi. We don't have a separate sentient species on Earth (at least that we know of), but of the species that come the closest (most primates), we don't eat, and I think most people would have a problem eating.
Of course, we have eaten or at least harvested some highly intelligent creatures with complex social structures and/or the proven ability to use and create tools--elephants, whales, and octopi all come to mind--but I think most people that engage or engaged in these practices were doing it without knowledge of the animal's intelligence. Of course some people still wouldn't care...but some societies still or have recently practiced real cannibalism. So there are always exceptions. But in general, I think most people in our society would object to eating Kilrathi, and it seems like moral values have changed little enough by the WC era that that would probably still hold.
On the rape issue...I highly doubt that most Kilrathi or humans would rape the other species for either pleasure or sexual gratification (except the possibility of a the occasional deviant). However, in most brutal societies (and some not so brutal...see Abu Gharib (sp?)), rape of some kind, or at least sexual torture, has been utilized as a highly effective means of coercion and torture. Human beings at least (not sure about Kilrathi), have extremely powerful psychological connections to their sexuality, either naturally occurring or societally induced, and those connections can be utilized to break or modify a person's mind and either gain information from them or torment them. Since we know the Kilrathi weren't above using torture for either end, and since they had psychologists that studied humans, I find it highly likely that some of the torments that human prisoners were put through were probably sexually tilted in nature.
I don't see why they should get some sort of preferential treatment.
