I mean, like everyone says, it's wish fulfillment, so I'm not gonna parrot everyone's post. In fact, I'm gonna double-down.
It's that one chick everyone wants to bang in school but she's only openly/secretly devoted to sucking your girth. It's the ultimate ego boost. Of course, everyone has different ways of getting off, but the idea of monopolizing an exclusive hot product with flaming demand is just insatiable to many. It's like owning a limited series Ferrari model, or having a signed pair of Yeezys. It's not that she's the "campus queen" that makes the troupe enticing. It's the throne in which you sit on where everyone else can only dream of even catching a glimpse of. Hell, she doesn't even need to be "campus queen". Just nabbing the most popular chick in class can warrant the same effect.
I feel like these posts claiming such troupes to be unrealistic are no-brainers akin to CN protagonists and slavery harem. It's pointing towards something GLARINGLY obvious. Of course these troupes don't exist in real life. It's like the blue sky; a fact so general it needs no mentioning.
Actually, thinking about it now, it's a little indicative of a prevailing issue. There's been a collection of such posts popping up, talking about loli characters and harem protagonists or shounen troupes or what not and prefacing it by saying they're unrealistic. Yeah, it's unrealistic, but the way these posts are phrased makes it sounds like it's intended as a wake-up call or a PSA, as if they're are under the impression that OTHER PEOPLE think such and such troupes exist in real life, (may or may not include OP). No shit, the sect killing young master is a genocidal psychopath, he just mowed down a school full of teens for slighting him wrong. Anyone with a frontal lobe knows that. The fact that someone felt the need to address its unrealistic nature felt as if they missed the point. McDonald's is unhealthy as fuck, but that's what people are here for. Sure, you can "criticize" them for what they do but it seems pointless to do so when the salad bar is just down the street, or that you could just cook from home instead.
Absurdity and exaggerations are what these troupes are made for. It's unrealistic, ego stroking, and definitely NOT fine dining experiences. It's bullshit, ye, but with a purpose. It's like a butter knife. It isn't the best knife to slice your favourite cuts of meat, nor is it useful in a house invasion situation, but holy SHIT can it spread butter like a champ.