better to be alone

Yesterday we went to our son's school to met his teachers and school directress to know their evaluation about our son's behaviour.And i was really shocked that one of his teacher told us to let our son enroll to the school about social gatherings because for them it is not normal for a child that don't participate to other childrens playing.And i told them how could he join if someone pushed his back and other child pull his scarf and roll it in his neck and he could hardly breath.Maybe he was frightened and he chooses to be alone.