well the reason ı support sena X kodoka realationship is because she is way too naive. it is highly possible she would be decieved by some useless guy.
i feel like ı am putting myself in Pegasus's place but this is what I feel. maybe ı like girls who falls in love. ı hate love that appeared outside of story timeline like "ı loved him since ı was kid" type stories. ı like seeing how a person falls in love described. seems like ı am trying to understand how people fall in love :P
other reasons would be that she is blonde and she is cute when she is honest