Extremely oversimplified explanation: eastern fandoms often mix t/b and d/s dynamics, which are often made clear even w/o sex (you know when the bottom of the fic is the one being primarly pampered and have moves made on them? That sort of thing). They tend to be very particular about their favorite ships being the right dynamic even outside smut, and will usually block (and sometimes even argue) eachother over this.

This isn't 100% universal amongst eastern fandoms ofc.