Dress cops up as soldiers, give them military equipment, train them in military tactics, tell them they're fighting a "war," and the consequences are predictable. These policies have taken a toll.
The amount force government authorities use, then, is no longer based not on what sort of threat a suspect poses to the government or those around him, but on the political implications of the laws being enforced. It isn't difficult to see how we get from here to pepper-spraying and beating peaceful protesters, particularly if the protesters are becoming a thorn in the side of politicians or are losing support from the public.