That brotherhood happens a lot in other government departments. Just watch what happens to whistle blowers. It also happens in any large organization (NGO's, Corporations etc), and more so where the organization is under pressure, understaffed (and has a hard time recruiting, as management will be loath to let go any head count), and has a lack of transparency and accountability.
There is a stigma attached to being a whistle blower aka snitch, and it applies to all groups and work environments from school children on up. Some of it is justified because sometimes the whistle blower/snitch has their own not so virtuous agenda in mind. Even those with the best intentions are going to be reluctant or soon discover the fact of this stigma. It is most extreme in a prison setting. Among the inmate population snitches are despised more than baby rapers, and in any serious disturbance or riot the first ones the rioters go after are the snitches.

Among law enforcement & military grunts, snitches are also not socially acceptable and are considered a tool of the darker side of management. In my department our internal investigative unit is called IG, Inspector General. Most of the investigators are also ex corrections officers and are about as popular as a dose of the clap. Been that way long before my time, and probably will continue to be long after I'm gone.