@TaylorsPoke naturally, it's just that some opinions and perspectives are fueled by wanting to see something.
It's really not much different from those that expected Nanami to win over Masiro, because they really wanted it to happen, even though the plot was setting up for Masiro to win in every way.
I wil say though that the nickname “Leftism_Is_A_Diseas” doesn't strike me as a particularly objective one, whose owner probably also sees what he wishes to see.
At the end of the day though, Minami's reactions are very normal for a teenager. Pretty much any teenager who was given a magical gender flip button would relish at the opportunity to use it as often as possible to have as much fun as possible and perhaps eventually grow bored. If you give such a button to a teenager, he will certainly instantly press it, and then proceed to masturbate and feel up his new opposite sex body as the first order of business.