So, you are saying he just plainly sucks and likes to suck? Well, I guess that's the simplest explanation, and simplest explanations are usually the most beautiful ones, but not in this case... It's always bothersome when the main character sucks. It was said he's the kind of simple guy who becomes very happy when he's complimented, so I guess evidence does support the claim he's a sucker, but I'd still want to retain some small hope he was just trying to teach Murasaki a lesson. It wouldn't be the first time such a method has been used to teach a lesson in anime.