Maybe it's just from the uke's star crossed eyes perspective? like he's so infatuated with the seme he things that everyone else must also fin the seme attractive.
I think homosexuality can still be so taboo in Japan that having someone popular, successful, etc. is basically saying it's not just freaks who are gay
and because this is a famous plot, that you can find in another movie/manga, even straight or yuri (you know, the poor/rich kids or the "ugly"/handsome type, boring person/star or someone flawless idk) because this doesn't happen in real life, people love this kind of story (and me too, i confess i'm weak!)
The seme's popularity thing wasn't really necessary for the plot. Why does he always have to be so prestigious and talented etc...?