I guess you haven't played the most recent version of the game. For several reasons, I have removed the option to rename the girls after v0.5.5.
Eve is indeed the "Childhood friend", Cassie is her friend. Jack, the MC, is the only one you can still rename. I still think that renaming the MC can be useful for immersion, but renaming the girls was useless and annoying. I won't make that mistake again in any hypothetical future game.
After v05.5, depending on the path you choose, you can also learn more about what has led Jack (MC) to make that decision in the past. I won't spoil it. But it's a human reaction.
Real people don't make life easy. I like that. Despite their best intentions, people are selfish, afraid, ashamed, shy and many other traits that make discussions and relationships ambiguous and uneasy to read. A lot of players don't like that. They want to be a manly hero who understands everything immediately and is always right, forward, confident, strong and successful. Jack isn't like that at all. He is a human being and so are the other characters of Summer Scent. They're all flawed and I believe that's what makes them endearing.