Raku's logic in that scene was....questionable at best.
She was pretty manly when they first introduced her.
She started out with a long manly face and flat as a board now she's feminine and curvy.
That's because she's the fucking best you shrew.
I wish I were Raku. He's a faggot but he can be with Tsugumi.
Why are the best things in life unavailable to us mortals?