Because the Thing you said Is So rare Harem That wont hold the Mc's main goal Maybe the thing ur explaining is 10% of harem and 90 % of them are Who Likes fuck every Female character they sees Most of them are mangas btw and Alot of weebs Liked it as long They sees some Big boobs and ass they're okay with it..
It’s probably got to do with the fact a lot of harems have naive or oblivious protagonists, and sometimes it can be quite annoying to see people all over them when they’re completely clueless. Or also some people, like myself, just don’t like when there’s a pairing you prefer but the other characters keep getting in the way.
I don't really get the deal on harems are they that bad? I personally don't care as long as the love interests are decent and aren't know holding back the mc. I get if the girl/boy/them are weak and hold back our main but if they are decent and don't fuck up a lot I don't really hate harems...why do you guys hate em?