Responses
the way I see it the older brother has a crush on the younger brother and wants nobody to get close to his younger brother so instead he asks them out and then dumps them to manipulate/chase away anyone that gets close. And then the younger brother just has a brother complex cuz he probably was a lonely kid till he got his stepbrother. Then the main characters is just in an unfortunate place lol
I think that the older brother just has a brother complex?
And the younger brother (who is probably the seme) has a brother complex too?
The MC (probably the uke) is just caught up in a misunderstanding between them.
I think that the older brother, once he sees that the younger brother (seme) likes the MC (uke), he will let up on the "I hate you." thing?