Mmmm interesting, i see things differently tho. I think that Sangwoo want Bum to kill his uncle.
But why huh?
Well, this is my theories:
1) Sangwoo "like/love" Bum (Actually I think he is more "obsess by him than "in love whith him" but it's another story), and he want him to be free from his uncle, and for Sangwoo yhe only way to do that is that Bum kill his own uncle (like a revenge).
2) Sangwoo is cold hearted psychopath (we all know that), so I think he just want to put Bum in a stressful/horrific situation, and force him to do horrible things. Remember, in the previous season Sangwoo forced Bum to killed that girl with an heart on the cheek. Probably he want to do the same thing again, with Bum's uncle.
So yeah, this is what I think. For me in both case Bum's uncle gonna die soon! Last scenario could be that Sangwoo gonna kill Bum's uncle himself, yeah, this is clearly possible.
Of course, it's surly more deep and complicated than that. Here I just wanted to expose my two main ideas about the " why the fuck did Sangwoo bring Bum's uncle as a present" lmao. :)
Enough reason why I think Sangwoo wants the uncle dead is as he said, he always gets in the way. Drinking... Uncles shirts... etc.
Maybe Sangwoo has fallen for Bum and doesn't want him to be involved in his crazy life but he knows that Bum won't leave willingly. So he gets the uncle to come take him away as he knows that's the only person that can take make Bum leave. Or maybe he doesn't give a shit about Bum and is tired of him and can't kill him for some reason and wants him to leave. Or maybe the uncle is there to help cut into slices for Bum's amusement. (๑•ㅂ•)و✧