This vicious crime reminds me so much of the police attacks discussed in this BBC article I read a few years ago, "Don't shoot, I'm disabled": https://www.bbc.co.uk/news/stories-45739335
I think that article might've been one of the first times I read about how US police training is often designed to produce confrontative, controlling, aggressive officer behaviour, and can encourage officers to assume bad intent and unnecessarily escalate situations. It would make sense that any member of the public who behaves at all unusually, like someone who's mentally unwell, is going to risk setting off that apparently hair-trigger response.
Add to that a racist society and a racist police force, where the assumed likelihood of ill-intent is already turned up way higher for Black people, where Black people's behaviour is more likely to be interpreted as aggressive, irrational or defiant, where Black children are perceived as older than white children, where police maybe feel they're more likely to get away with excessive force when it's a Black victim, where police cover for each other, and where the most extremely racist, violent people deemed unsuitable to be officers can just get a job in the next county over… I can't imagine how terrifying it must be to be in Sonya Massey's situation — frightened by the possibility of an intruder, vulnerable and maybe confused due to mental illness, and at heightened risk from police because your skin's not white.
The UK isn't all wonderful for mentally ill or disabled people either, obviously, nor for people from minority groups. There's still ignorance, lack of understanding of health issues or difference, and of course racism. But I don't think our police have the same kind of training that encourages officers to think everyone's about to jump them with a weapon, or to believe that every situation needs to be controlled and subdued with dominating force rather than de-escalated. And they don't routinely have guns, of course.
I have ASD and bipolar disorder, have very occasionally had contact with police when unwell, and I've always found them calm, kind and respectful. I know things may have gone differently if I were Black and/or male, and many people's experiences with UK police are very different — a documentary I saw a few months ago exposed some appalling police behaviour towards people with mental illness. But I can say that if UK police routinely took this kind of paranoid, self-protecting, aggressive approach, with the incomprehensible yelling and pointing of guns, some of my contacts with police could've ended quite differently. It makes me go cold to think about it.