I'd say it's because SHE seems fine with it; except then you have the scene with Em where he can go against her clearly expressed wishes, to apparently no ill effect - although I suppose that second one's a player choice, so it's maybe a bit different.
The main thing *I* still find strange and frustrating is that the MC on the harem route is STILL insisting that only Hannah matters at every possible opportunity, right up to and including chapter 8 - so it really feels like there is only one actual LI, regardless of path, and the others are still just being treated like nothing more than temporary side-girls, which is disappointing.
I'm holding on to hope for that to change still, especially with the little line about how MC's emotions empower his magic (possibly meaning that as he accepts his actual feelings of love for the other girls on a good path, he'll get stronger).