hototogisu
Poked the bear!!!!!
None of these arguments make very much sense.
I doubt very many of us have been raped or know many more people who have been raped than have been murdered. Whether or not characters who kill for fun are portrayed as despicable human beings is irrelevant, because the same is more or less true of the characters who rape. Furthermore, the only reason most villains have ulterior motivations for murder these days was in reaction to past norms where villains were evil for the sake of evil and murder for ****s and giggles. It wasn't treated any differently then, and people didn't excuse violence any less.
Motive/justification really has nothing to do with why they're treated differently. It has more to do with response. The thought of being raped is more terrifying and disturbing than the thought of being murdered, just as the thought of being tortured is more terrifying and disturbing than the thought of being murdered.
I don't think you can claim everybody else is wrong when the central thrust of your argument is as subjective as this.