>>3073222Quick history lesson:
Back in the late 90s/early 2000s, in English speaking places "yaoi" was used for NSFW, and "shounen-ai" was used for SFW. Recently, people found out that the Japanese use "BL" and started using that too.
In Japan, yaoi and BL is the same thing and there's no different terms for NSFW/SFW, they just use "R18" labels when needed. Using "BL" is a lot more common than using "yaoi" though. Turns out that they never used "shounen-ai" at all and it's actually some thing about little boys there.
I think English speakers tried to create the whole yaoi/shounen-ai split for nsfw/sfw because there's so much underage into that kind of thing in America and a lot of sex negativity. Like I've actually seen a lot of English speaking anime fans get really angry finding out there's a harmless sex scene in their romance manga for some reason.