Not because they can’t be done right and you can’t teach people to use them.
But because there’s a slippery slope of human nature where people want to offload the burden of decision to a machine, an oracle, a die, a set of bird intestines. The genie is out and they will do that again and again, but in a professional organization, like police, one can make a decision of creating fewer opportunities for such catastrophes.
The rule is that people shouldn’t use machines above their brains, as one other commenter says, and they should only use this in a logical OR with their own judgment made earlier, as another commenter says, but the problem is in human nature and I’d rather not introduce this particular point of failure to police, politics, anything juridical and military.