This is not a case of one bad police department, rather it seems that this behavior is intentional and part of the country-wide protocol.

This is also violence that is, in some cases, rare for many of these cities and departments. There were some cities that did not previously have protocol around chemical weapon usage, because before these protests chemical weapons had only been used in specific SWAT team situations. Nevertheless, their police forces still deployed tear gas on protestors. The response to the first wave of protests has normalized this violence, despite public outcry and resistance.