I don't super get the whole "im just the dad that abandoned him" perspective. Maybe if he really is that resentful, Satsuki wouldn't be receptive seeing his dad, but like. Mom has full custody. He can't see his kids, but if one of them is in trouble, can't he go see him?? I think it's worse in the long run that Uncle is hiding that he knows his dad. I've never been in that sort of situation before, though, so this is me just wondering.
I also wonder if Satsuki will work through his "het" attraction, or if he'll discover gay people exist and he's one of them.
That could be one angle, but I still feel this is a literal confession of guilt. Satsuki is probably aware of homosexuality, it's harder and harder nowadays not to, it's just that he is gynophilic at this point. Does this mean he can't break through that? No, but that's a hurdle he's just starting to approach. He's realized the attraction, but it's in a way that is not respectful of Rika and so he's stuck in guilt mode right now. We'll see him work through it.