This was tagged yaoi… not shonen ai
Maybe cause they're not REAL PEOPLE
Wait what’s the difference
Shounen AI just means that the story is BL it doesn't mean there will not be any mature scenes or smut. I have seen lots of these tagged Shounen AI and Yaoi at the same time because the story includes both.
The difference is just that it only depicts a relationship between males if it is also tagged Yaoi, mature and smutnthen you will see smut. But if you dont see these tags you might just read a fluffy story of two boys in a fluffy non sexual relationship. That is what that person meant but it doesn't necessarily mean there won't be any smut. But only if tagged correctly.
They are minors in high school why is anyone expecting them to have sex?