Click here to access article by Paul Craig Roberts from Strategic Culture Foundation.
Roberts asks some very important questions and tries to understand this violent police behavior and the assault on the police as witnessed in Dallas. He comes fairly close (for a conservative) in the final paragraphs.
For those who understand that we live in a class structured society in which one self-serving class rules to the disadvantage of the other classes, the explanation is becoming obvious. The police as well as all official agencies of violent coercion exist ultimately to secure the interests of the über-class. This latter class is the capitalist class whose control over the world and its own nation is being threatened in countless ways, they are feeling increasing insecure and prone to violent solutions, and instilling fear in the population tends to increase the latter's support for more police actions and restrictions on civil rights.
Clearly they must be recruiting people who have a proclivity to violence and racism, training them to use force whenever it suits them, and assuring them that they can do this with complete impunity. There is evidence, some of which Roberts supplies, to support the second hypothesis, and the record over many years clearly shows that police rarely receive any punishment for murdering people. Actually they are rewarded with a paid vacation (paid "administrative leave").