yeah by definition that's true. I just always thought that the tags were chosen by the uploaders or like expectations of what the manga will entail. I've seen tags change overtime multiple times. They go from shounen ai to yaoi and reversed, because people expect them to cross the sexual line, but they don't or suddenly they do.
(but if that tag was placed by the author themself then indeed we won't be in luck hehe)

Tbh I saw a lot of people saying that these two wouldn’t have seggs bc of the age and stuff (which understandable) but then the panels of them literally tongue kissing are pointing in a diff direction lmao