I don't think Ren/Corn's behaviour is all that strange.He loves Kyouko, so it's only naturel that he wants her to show her feelings for Corn.
As far as he knows, she sees Ren as a 'sempai', and seeing that her promise to her sempai is just as important for her as Corn, is jarring.
He shouldn't take it out on Kyouko though (as he realises as well).
But it looks like he's gonna get what he deserves: a kiss from Kyouko while knowing she's acting.
I love to see that happening though, Kyouko's reaction afterwards will pe priceless.