im always surprised when ppl start going ''PLS NO USAGI DROP'', even in cases when u can see it happening naturally coz its a thing that can happen in certain circunstances like developing feelings for the person that literally saved you from slavery, death, torture, rape, a life of poverty, etc.
Its pretty much the same with those witch gathering mangas, boy gets saved by girl, boy grows lo love the girl, its just that simple, but i think that the ''PLS NO BUNNY DROP'' comes from being presented with a premise and turning it around at the end, like Usagi drop did, but in mangas like these u can see it happening early so u aren't being deceived.
Now if things went the usagi way in ''If It's for My Daughter, I'd Even Defeat a Demon Lord'' then u can feel rightfully deceived, coz it defeats the whole premise of the manga so oviously ppl would feel betrayed.
Now in some cases the manga shows the mc being a Dadcon, in those cases im good for both endings coz its open for both in that case