Responses
It's because it's implied in the story that she liked a friend that's the same gender because of the flashback that she has a couple of chapters ago, but she felt weird about it because she thought it was wrong, and now she's trying to get Haebeom to be "normal" because she doesn't want him to go through that feeling too
I get that the girl probably went through a similar experience as Haebeom, liking a friend that's the same gender. However, that is no reason for her to try and do something like this just because she went through something like this. Just because hers ended up not a happy ending doesn't mean everyone else's story will be the same.
Also, I get that she's just a kid, but she knows what's right and wrong and she should be able to know that trying to revert someone back to being straight isn't right.
(Sorry if the English is bad, it's not my first language)