I do think the fact that the boy's love tag is kinda weird..
'Hikaru' has confessed his love, but he himself has confirmed that he doesn't know whether it's romantic or platonic. Because he doesn't feel emotions the same way we humans do. But he does know that he cares for Yoshiki deeply so if you pass that off as gay, so be it.
Of course, This Manga is probably one of the best I've ever read. The art, the dialogues, world building and character interaction is beautiful.
I also would like to add how tragic yet comforting Yoshiki and 'Hikaru's' relationship is.
'Hikaru' wants to protect to Yoshiki, but 'Hikaru' being around Yoshiki is actively hurting him.
Yoshiki misses Hikaru alot, so I don't know if Yoshiki likes 'Hikaru' as much as he liked Hikaru.
And Yoshiki himself said the only reason he's keeping 'Hikaru' around is for his own ego/self benefit.
Yoshiki doesn't wanna be alone and he is the one who wants to 'save Hikaru' (He said it in Ch28, but I don't understand what he exactly meant)
How ever you see it, this Manga is spectacular, and if you still don't know why, go get some glasses mate.