Actually people who said bad about Harem genre Tag are likely never read a good harem story. Base on my experience a majority of harem genre out there are fake especially the famous Japanese harem with no touch theme like "To love Ru". If you grow up watching and reading Japanese fake harem I can understood where your hatred comes from.
Why Harem is good for me?
Let's stop being a hypocrite first harem exist it also known as having an affair in real life. And Majority of man out there have 2 or more women with them. This genre is fantasy base so things that is wrong in real life is just being exaggerated to satisfy some reader and I see nothing wrong in that. Rather than saying that it is wrong and bad try correcting one in real life if you think you can justify yourself.
Next in harem the unification and balance relationship between women is interesting especially when this women seems enemy at first then became friends because they love the same man or vice versa. Some times this girls having a cat fight looks cute and so on.
Next Harem does not equal to Hentai. This influence is widely spread in Japanese tradition where Harem is just a man having sex with many women. Real Harem is about man trying to pursued many love and not just limited to sex. A fickle hearted man who easily fall in love and how he do his best for the girl looks nice to me. Having A man pursue a women is an interesting Romance what's more if this man is doing it with a lot of women in different circumstances.
And lastly I have nothing against people who hated harem since like I said I do know why you hated it but it is just a matter of interest theirs no wrong in bad in it. Sadly majority of so called Harem haters are just hypocrites who just want attention of sort of just to fling something with them. I encounter lot of this people who say they hated Harem and commented badly on it AFTER reading a Harem story to the very end...