[Hikikomori]

>Not true, the context I have seen it very much included being a witness who is not a person of interest to the police. It especially explicitly included that situation.

Even without context, its good advice. By talking to them you might even be confessing to some crime that you didn't even know exist.

>That is egregious abuse of power. The layers I have in mind were not explicitly mentioning that high level of lawlessness from the police.

That's the entire point. This idealized version of the police you seem to have, maybe some European countries come close it due to their requirements on officers and training, is not reality. Departments allow officers that act like this to resign so they can move to a different department.