Then you should also condemn everything else that is bad in fiction.
You shouldnt enjoy storys with killing, robbery, bribery, drug use, general violence etc.
People arent ok with it because they think pedophilia/ hebephilia is good or right. The reason they are ok with it is because this isnt a real story. The kid doesn't exist, the uncle doesnt exists. This didnt happen. Of course its wrong for an older person to go after a teen / child, I doubt ppl here would think otherwise. It's not wrong to read a fictional story about it just like it's not wrong to read a fictional story about violence.
idc if it's fiction, but incest and pedophilia is still messed up shit even if some dumb fucks think it's not. the main problem with incest is that they're blood related, not because they get deformed babies from it. plus it's weird pedophilic shit. you can call it an opinion but fact is pedophilia and incest is still wrong, in fiction and reality.