I feel its not anything to do with gender....Its more to do with fangirling.
It could be favorite actor or just for what ever reason the character that you favor what ever their character traits are. People can even talk in favor of full on vamps or villains with no back story or anything to give them a more human feeling other than maybe just their feelings of love or attachment or obsession to another character which they find endearing.
From there on all that the other characters how ever mundane and inconsequential their faults are compared to murder, torture, blackmail, fake rape charges, you name it that those whom they favor do to total innocents, will still be considered better.
I've seen this happen in Beyhad forum and I can bet you would see this happen in Beyhad 2 as well...(Edit: I actually saw a really cool bunch of great jenny fans who are able to differentiate right and wrong even if its fiction and though they lauded Jenny's performance they were clearly against the characters actions and did not want her to succeed in harming all the other innocents in the show and did not ship the male lead with her...Even though I didn't interact with them it felt good to see people being real to real life values even in fiction.)
That is all there is to it I feel. Otherwise I have not seen such heinous crimes and actions lauded as still better than other faults that are nowhere in league with things like murder, torture etc. IF it is fiction people would not think twice calling anything and everything better than what the person they don't favor do....
I don't have a problem people being interested and invested in a particular character no matter how dark they are, but when they justify and say other more positive characters are still worse and deserve to be harmed and what not by these dark characters and gleefully celebrate such actions I feel really disturbed. But I tell myself its only because its fiction and hope against hope it would not have any relevance to real life situations.
What to do as long as famous actors and good looking people are used to portray the most heinous crimes and glorified as such brilliant beings, by makers, there would surely be an audiance who appreciate it too.