Hmm... yeah, this really took a turn for the worse, it leaves a bad taste... MC shouldn't have delayed the response to her confession in any way, Kanou is right that Matsukata's confession and relation to Kanou has nothing to do with it. The reason why it's so bad it's because the MC says that he wants to change but in this scene it clearly shows that he certainly doesn't want to because he's avoiding the problem there again. Now he's just making the girl miserable, himself miserable and likely other characters miserable in the end and I am guessing this is all because the author wants to setup the relationship between the MC and the heroine =-=... it's not satisfactory when it feels so forced...
EDIT: Forgot to mention the scene where he just greets Matsukata casually even knowing the confession, making the girl hang even though he CLEARLY wanted to change yet here we go again with the running away. It's not that it's not possible, but when you introduce his growth already with the sports festival ark and show how much he is willing to do to change then dropping all that, when he was actually progressing well with the trip group, to advance the flimsy romance troupe of this work... is just so blergh x-x there's like no rhyme or reason for it!