It might of started that way, but if a comic gets more popular main stream in Japan it will just turn to bl to sell more with younger people. It happened with a tiger one (forgot the name) and a weird one with adopted brothers.
Can i ask something? Is bl stuffs really popular in japan? I mean the author do use bl fanservises a lot. For example, Owari no seraph and My hero academia. I know mha is not bl or anything but baku almost dying for his deku bro twice screams gay to me.
It's popular, and a lot of female manga artist start with making djs that are yaoi. Liking manga is still nerd thing, but when women are like it, it's stigmatized as only liking yaoi.
Aw I was tricked. I get why there is a yaoi tag but... There's no chance those 2 will have sex in the future T_T Too bad!