This was in the proto-BL magazine June, and while Yashiro herself was never part of the proto-BL/June sphere, she was very well aware of the magazine's target demographic. The work is deliberately structured to have different readings depending on who goes through it; the general public can view it as a story between two very close brothers, whereas the proto-fujoshi could enjoy the tanbi (aesthetic) atmosphere and relish in the brothers' relationship in full, even if it's not outright incest. It is intentional.