This, a lot , A LOT of people , especially is US doesnt know that you can marry step siblings and think its a taboo, thats why there's so many kink and porno about step siblings over there,
Not only non related blood step sibling, almost every where in world, its the norm and that its okay to marry your 3rd or 4th remove far cousins, but A LOT of people doesnt know that and also thinks its incest taboo, these kind of things are normal and usual when you have a large and big multigenerational families like asians , including chinese, japanese, indians and so much more in most south east asian countries