ao no exorcist fandom question

dont get me wrong, i love ao no exorcist and the characters, plot, lore and animations and shit but how can a good chunk of the fandom ship the twins together??? like how???? usually I'm completely fine with weird ships that don't make sense and rare-pairs and shit but incest??????? like why??? just cuz they don't look alike doesn't mean incest makes sense?? (just saying, if u gonna go super saiyan in an answer and try to roast me or something, then gtfo (╬￣皿￣)凸 if ur gonna explain urself and answer like the human being yall are, then please, go ahead and answer, that's why I'm asking. but don't just get mad, getting mad makes literally any civilized person not want to listen, but by all means, you can curse me all you want in your head but in ur answer, be calm, collected, and answer so that your argument will be recognized) (づ￣ ³￣)づ