Because some people can say they love someone.... and then fuck someone else? Just because you can't do it, doesn't mean others can't. Love, emotions, and attachments made, don't just work one way. Like this whole thing sounds more like you can't do it, you can't manage it, or you can't get into, therefore. That ain't how life works. I like many others, have played harem games. I like many others, grow to care about many, some, or all the LI's. Depending on the game. And because you personally can't get into what's on offer. And haven't found that one game to give you the multiple warm and fuzzies. Does not = it doesn't work.... it doesn't work for you.
My love for LI's won't magically disappear because there are multiple. I have had no issue spending whatever allotted time a dev will allow, with multiple women. And coming out the other end with all of them. If the characters are done right. I would have little issue, caring for 1, 2, or more of the current LI's on offer. Because I think most of them are well done in this game. I'll admit that it gets a bit much when the number is huge. But that's just me. I wouldn't then take my inability to get onboard with it. To make the blanket statement of it wouldn't work. That's the only thing I was commenting on.