Please do not make sweeping generalizations about a group of people based on the misinformed actions of a few. The overwhelming majority of police officers are intelligent and make rational choices in the line of duty. This incident wasn't so much caused by ineptitude or stupidity as it was by a lack of clear communication and incorrect decision-making based on that lack of communication.
The majority of police officers act like terrible people, because even if they don't start that way and even if they aren't that way outside of the job (at least at first) they end up deeply enmeshed in a system that encourages them to be terrible people in order to fit in and succeed. While there are exceptions, departments with high standards and good policies, in most police departments around the country police are little more than gangsters with official recognition. They believe the law does not apply to them, that they are better than non-police-officers, that their life and safety is more important than non-police-officers, and that protecting their "brothers in blue" is far,
far more important than upholding the law.
Of course, there are exceptions. But this isn't a case of bad apples. This is a case of a few good apples in a barrel of bad ones somehow able to resist the rot. Even if you only toss good apples in from now on, most won't stay good for long in that kind of environment.
This comes from someone with police officers in the family, who knows quite a few police officers, and who has interacted with the police in a lot of different places around the US. Even the ones that aren't outright bad have a really bad understanding of who they are and what their role is - they either see themselves as a budding action hero, or someone with a sweet gig that lets them play the bully they always wanted to be, or even both. Very few of them see themselves as servants of the public.
The overwhelming majority of police officers are poorly trained, poorly supervised, and poorly disciplined when they fuck up. I have a lot of sympathy for them - a good portion of them get into the force with good intent. But they still end up as bad people doing bad things all the same, and the ones who actually stay dedicated to the ideals every police officer is supposed to uphold seem to get a FUCKTON of shit thrown at them constantly.
Perhaps they made intelligent and rational choices based on the information they had available. But that does not mean they made "good" choices based on that information. When you value yourself, or your friends, or your own sense of adventure over the well-being of the public, the intelligent and rational choice leads to... well... this. Which is why we have laws and rules, in large part - so that the "intelligent and rational" choice also happens to be the
correct choice, the choice we want them to make.
In the police force, this pressure generally isn't brought to bear except for protecting your "brothers", so it's no surprise we get so many people fucking up so badly and horrible miscarriages of justice as the result. They made rational and intelligent choices that also happen to be horribly immoral and fucked up choices, because that's what the system and environment encourages.