Quit bitching about it on Danbooru. This isn't the place for it. Try complaining to the artists themselves, rather than a bunch of unrelated people, and see where that gets you.
Apparently the tags have gone back and forth last year but even from using deepl to translate the commentary
They'll know it's a boy.
I heard from someone in Thailand or the Philippines that even boys can create cleavage with a nouveau bra.
The artist obviously intended that Ryo's just creating the illusion of breasts, he's not somehow a genderswapped futanari, the pixiv post is even tagged oppai shota, otoko no ko, and "too cute to be a girl"
Based on mtl of the artist commentary mentions using a NuBra so that even guys could appear to have breasts. Google search results of crossdressing and NuBra does being up Reddit posts talking about using NuBra to mimic breasts for crossdressing.
