I already explained why I hate it
I'd be alright with that if this was the only case of Oda being a shit writer when it comes to backstories and most women he writes in general, but it's far from that, so far from it it's kind of sad.
I mean he didn't need to do this to her, I understand he has to make Kuma's backstory very sad and all that, but at this point it's a little exaggerated.
He already had his parents die (and has no other family that we know of), was a slave for the CDs until God Valley as a child, lived in a shithole with a terrible king that was full of old people (sans Kuma and Ginny ofc), and now his best friend/lover got enslaved, raped, and killed and he has to take care of the baby.
That's more than enough imo, and we still have to see why he became a slave again as well.