Why do آپ think Gouenji turned to the dark side. And how did he get to be the leader?

I think something bad happened to him that has something to do with soccer, then maybe after that SOMEONE brainwashed him, for him to think that it is because of soccer, that, that bad event happened.. so he wants to destroy it..

He became the leader in a some sort of election, this election is mentioned in Episode 21 when Hibiki announced his candidacy to be the Fifth Sector Leader. Also, one of his men کہا that no one has ever made their candidacy since Gouenji(Ishido) made his inauguration..

EDIT1: Some شائقین think that the earrings controls him. :P I think he got into an amnesia, along with the earrings.

I think someone is controlling him

i think its something related to Soccer, something bad happened and Soccer was included in the reasons

I think that someone obligated him یا something like that !! XP
Goenji-kun why? T.T
یا that something bad happends to him then a bad guy gave to him the earings that know he wear and it control him !!