I just watched it on youtube - lovely children, even the bully in the end 
I though it mainly shows the different characters emerging. A lot of the things they said were probably what they'd heard their parents saying.
After retiring I had a part-time job helping a Downs girl to integrate in a class of "normal" 4 year olds. There was one pair of girls , twins, who showed so much empathy and kindness towards her. The others were tolerant , she could be difficult.
There was also a heavyweight boy, very like Chaim. I felt rather sorry for him, he was so different because of his size. He grew up to be a decent teenager.
I remember the teacher in charge saying that most of the problems at this age would change, especially a little girl who refused to speak, and she was right.