Well, yes. Because harem endings typically mean that the protagonist is reduced to a damp red smear and maybe a bit of ground chuck.
This please Khorne to take bloodshed from what would be vapid carnality.
I mean, aside from the Mane 6, where I mostly do it because I honestly can't see them divvying up into 3 OTPs with one another but it's mean to leave unentangled ponies out in the cold.
I am fond of liberal uses of duck tape...