"Dragnet" had a strong tendency towards preaching and simplistic moralizing, seeing pretty much everything in black-and-white. This particular episode does it more so than most. Friday and Gannon are assigned to the western San Fernando Valley, which has experienced a huge population explosion and a subsequent increase in juvenile crime. They're investigating a rash of shoplifting committed by teenagers, and discover that a ring of youths at a local high school calling themselves "Tbe Mod Squad" requires its members to steal merchandise totaling $20 at local stores in order to belong to the "club". Webb's extremely conservative political and social beliefs are more evident in this episode than in most, and the "causes" of all these problems are shown to be such things as the "new morality" that kids see in the media--Friday's captain complains that "even homosexuality is praised; how do you fight that?"--"permissive" parents, "weird" clothes, and the usual litany of social "ills" that conservatives were complaining about then and are complaining about today.
Some things never change.
Some things never change.