Perhaps a more productive way to address this issue would be to speak with the boy’s principal and share with him your ideas of what lessons should be shared with the students. It is very possible that the school spoke at length about it but it did not affect your son.
It is not not strange for a 12 year old to not care about any communal issue especially if it will not have any effect on the video game he plans to play that afternoon.
Do you remember being a community activist at age 12?