In terms of game play? Labeled harems tend to be repulsive because along with incest they are #1 contributors (by far) to the universal problems most of these games have as far as producing quality stories and writing to accompany the erotic renders they are in the business of peddling. The moment you have a dev "trying" to make a "harem game", or even more so having that word itself pop up in the script dialog...99/100 times that aspect of the game has basically already gone to eyeroll inducing shit. Especially among the majority the usa based market crowd who aren;t going to be confusing a fap game with their RL reality.
That said I love being given the option to have sex with every girl a game has to offer. Which can still be done without labeling it a "harem", putting a middle eastern theme spin on it's story presentation, or having a writer concern himself with some extremist need a bunch of consistently vocal pirate posters on F95 have with having clearly defined/worded confirmation that every pixel girl in a game they have sex with is "theirs".
Maybe one day we can have an alternative tag called "player" for that