Are you actually reading with open eyes? Or just biases for not liking a character. She supports Yuu for Enemoto because her pushes wasn't enough for both of them to realize the love that they developed over the years of friendship. Everyone needs a catalyst for something to develop.
The "passionate seeking" seems you know the meaning of it but you're annoyed because it wasn't the other girl. BIAS
Her manipulative antics? Finally, feels like girl in real life not some generic anime girls. Also the fact that she's still have conscience about her acts and still tells the truth in the end is the sign of good char.
MC didn't fall for small antics but a major one which actually affect him in the long run, so that doesn't make him that stupid. Why would he question her for something they always do for years? Plus she supports him that just increases his debt for her.
Be honest you just hate a healthy friendship, the fact that this is just their first major fight for many years shows how deep their bond is.
