The only thing that ruined it for me...(spoilers)

Yeah, I see your point, and I felt similarly about the development of the teacher as having been married to the father, too. I agree all the chat scenes were a lot, but they illustrated three things which maybe put the those scenes in a less repetative light.

1. It made clear the alienation of the boy from his own personal legacy and the discussion in general and from the people arguing.

2. It was effective in contrasting those "chat" interactions to those of the boy with his teacher and uncle. In a way he's stepping out form the world of ideology and religious exclusion he was indoctrinated with by his father to learn more about his parents himself as people, not figures in a terrorist plot, or victims of their religious upbringing.

3. That moment where we shift from the boy chatting to the girl on screen, to the girl chatting to him on her screen is so effective, it's where we really see the impact of the grandfather in a sort of way, and the monstrous dimensions we take on when we enter discussions of terrorism (religion) in a dogmatic way...

Bottom line I felt it wasn't only about the danger/absurdity of ethnic superiority and religious exclusion/fanaticism and the out-right horror of terrorism. There were a lot of themes and ideas I felt those moments were showing, which is why I didn't feel it became repetitive in this respect.