Carlson is shown to be one of the purest forms of social destruction that Steinbeck envisions.  On one hand, he advocates without any regard or affect regarding his actions.  This is best seen when he urges the group to give him the go ahead in killing Candy's dog.  Carlson has little in way of sensitivity, reflection, or affect.  He is the voice of the common denominator, the herd mentality, where so much in way of negativity is evident.  In a world that is complex and nuanced with intricacies, Carlson is the force that renders an easy and reductive answer to this.  For Steinbeck, this is a cause for worry as individuals who lack the will to search for complex approaches to complex problems will easily capitulate to the likes of Carlson and their sources of advocacy.  Carlson is insensitive, demonstrated in the ending where he fails to understand George's pain and Slim's assistance in a time of ultimate need.  Carlson's destructiveness is shown when he is almost "thrilled" to join Curley in the hunt for Lennie.  In this, there is a wanton destruction evident to his characterization.