Ignorance of terminal ballistics (and of the physiological requirements to quickly incapacitate an attacker) is nearly universal, not just amongst police departments, but in the military and civilian worlds too. Fortunately, the military has a small group of people that have been working to educate more of the military decision-makers. That's *beginning* to happen more with police departments as well, but there are still many, many departments whose "ballistic testing" means shooting at water jugs or watermelons and using those results to pick a load.
Even departments with much more sophisticated testing methods often get tripped up by the department's legal staff, requiring a bullet with too little penetration "just in case". And in other departments, the chief or armorer may have fallen for someone's marketing and dictated that his "pet load" be the duty load. Finally, there are departments where rifles are simply so far down the priority list that the only consideration is saving money (think: Wolf ammo!).
Too many people assume that whatever the cops or military carries must be "the best!" That's occasionally true, but more often it's far from being the case.
-Troy