I read nothing into the slogan other then a very bad choice of words. Yes, the superiors should have stopped this.
I have no problems with policemen doing their job. In fact, most policemen in the major city where I live have served their country on active duty or serve in the Guard or Reserve.
While politically incorrect, I would rather have criminals with PTSD then either our law enforcement officers and/or our military.
Objectively, most people say I’ve had a pretty colorful career. From my perspective, I’d say these guys need to have a real serious slap-down. I get humor, have a pretty good sense of humor. But the problem is that these kids and their leadership didn’t have what is referred to as “common sense” If a cop lacks common sense, who, besides that individual gets harmed? The public. We should pay them more, understand their problems, and demand as much professionalism as they can muster. The “humor” of this tee shirt was certainly intended for the class. Unfortunately, it wasn’t funny and should have been stopped at the stage when it was still just a suggestion. That’s where the administration comes in. There is no doubt in my mind that someone on the staff of the academy knew about this. That person should have stepped up and prevented it’s use. It was unprofessional. Further, he/she should have followed up with a serious discussion of the role of the police officer and the importance of professionalism.