Seriously... The girl did him dirty... she could and should have defend him in front of her friends but she didn't... I understand why the guy is very upset of course... but... before all these happened, MC has the belief that Kitaoka is not what other people think about her, he also got the friend from the all girl's school vetting for it... then... his friend gave him an advice, "this might be just a misunderstanding" not the exact words but what he implies... and then this... kimura guy basically confirmed that Kitaoka wants to apologize and explain things...
And you know what the MC wants to do? run away...
The girl is an idiot for not being honest... while the MC is an idiot for not giving her the chance to talk...
there is no way this relationship will amount to anything if ever they get together... Better the MC just continue to run away and forget about her while FMC should just find another guy...