There is a long history of confusion between psychology/psychiatry, enforcement and community affairs in helping protect and treat sufferers. It is not per say ignorance it is a socio economic (Class) discriminative where informants, reports, and snitches (tyrants) come to the answer. This leads to communist block associative linguistics 'Cuo' points in discriminative practices and terrorist emotional influential 'What are you' and 'Short end of the stick' corrupt accessed professional work environments and foreign illegal intent and motive.
The underlying premise to your question is absurd. Your desire to promote activism undermines the quality of your inquiry. The very existence of a law enforcement agency is predicated upon the common understanding that it is better to have it acting on behalf of the people than not. The idea of "actions on behalf..." and paying for it through taxation and being overseen by duly elected officials is at the core of the social contract which we all buy into and depend upon for every other social structure and process. A healthy, responsible and fully-resourced law enforcement body -- subject to an equally-situated polity and judiciary -- is critical to all forms of large-scale society.
Perversions of that contract (from either side) are not justification for questioning the legitimacy of the authorities inherent in law enforcement. While procedures and organizational structures and cultures may need review, what is happening in many developing countries -- including what the article describes what is happening in Brazil -- is not grounds for dismembering the only justifiable coercive power within a state. It is indeed tragic and terrible, but questioning the validity of law enforcement as a core institution of society is either foolishness or deviousness. To be certain, sometimes institutions need to be re-built, but there is never just one or two causes behind an institution run amok; there are typically dozens of reasons, spanning decades, and most or all corners of society have some culpability in the problematic situation.
Here in the USA, we are just getting over experiencing movements such as BLM, the New Black Panthers, and a handful of others, who were really not effective at creating a message or a platform for countering a widely-supported network of law enforcement institutions. The groups were ineffective because they could not demonstrate a critical break down that required redress of the system. At most, what was needed was additional checks on procedures -- but mainly, we just needed to let the system work, unobstructed by political theater. In the end, the political parties here realized that law enforcement in its current mode is not only a critical , but also that the social contract did not beak down despite political fear-mongering (or pandering) from various corners. That is to say, the system largely works very well without reform. The only sector of society that I can find that benefited from the national debate are the companies that manufacture body cameras that many police organizations now use.
(part B) Now, if you wanted to observe and intervene in a socially useful and responsible way, you attack the underlying causes of this particular situation. Without even re-reading the article, you can automatically respond with a plan for solving corruption, poverty, and fairness of political and legal processes. An alternative interpretation of these are transparency, improving popular education & capital investment, and democratic institutions with vast assistance from outside/foreign sources for all of the above. once these mechanisms are in place, then law enforcement bodies will have a much easier time of it without resorting to criminal behavior simply because the people will buy into a new system in and around the favelas.
Yes, this is hugely over-simplified, but academic forums such as these always are.