The locals don't tolerate differences very well. They also adhere to societal norms and rules with great rigour. There is a specific method that things are done, and anyone who veers off course is dealt with harshly. Small instances of this may be seen throughout the novel, with routine public reprimands for things like bringing food home or having hair ribbons undone. We may observe how pervasive this habit is by considering the conversation of Fritz.
Jonas considers it completely normal to treat Fritz this way, punishing him because he is awkward. It is similar to the story we hear later about how Asher was beaten as a toddler for using the wrong word. Conformity is the ultimate goal, and children are socialized from a young age to not only accept it but enforce it. Thus Jonas looks down on Fritz.
Despite being only nine years old, Fritz is well known. Not only that, but his parents are also despised by the neighbourhood. They must be doing something incorrectly for Fritz to be such an idiot. It is a parent's responsibility to instil in their children the values of the community.
It is frightening how Jonas dismisses Fritz as violating community norms when he is simply acting like most nine-year-old boys would. Perfection is not simply desired, but also expected in Jonas' society. People are disciplined out of anything less than perfection from a young age. If everything else fails, there is always release.