I feel like there must be an error in translation, an MC being angry, explaining from A to Z why he's mad, while having a clear discussion about the problem at hand. Impossible, the technology's is not supposed to be there yet.
Then again, can he really complain that this 15 year old girl was immature ?
@Gravewind You'd be surprised on how potty mouthed some otakus IRL are. I knew some back in high school. I mean, think about it. Otakus are generally awkward persons socially. They are definitely not your gold standard for manners. At least from my experience. In fact, this MC is too nice and considerate if you think about him supposed to be a socially awkward virgin, or whatever.