The only people that are jealous/mad are the thots and thot lovers.
This is what happens when a writer starts a story using fanservice/slutty girls to attract readers but then making her (the MC's) competition too strong.
-Face it, some women are never meant to be married, they are to be passed around as prostitutes/"thots". Miku falls under this category.
-Women like Fuji, are made to be loyal brides.
It's Lust vs Love.
Lust is abundant in our everyday lives. Love on the other hand, is not so common.
This is why the "side character" is so popular.
A similar problem with Kiss x Sis, it was Lust vs Love and it tore the fanbase apart. The "lewd" readers wanted the sisters to win, the "love" readers wanted teacher to win, and the "loner/forsaken" readers wanted the shy pee girl to win.
The only reason people argue about these meaningless things, is because everyone wants their "idea" of a good ending. All this ends up doing is dividing the fanbase so much that it forces the author to either go with a harem/open ending, or picking who is shouting/complaining the loudest.