The public notion of good policing and the actual practices police departments follow have been diverging for several decades (if they ever converged). What we're seeing right now is not some inexplicable increase in bad behavior or cops deliberately targeting journalists. For modern American police this is just business as usual, except the volume of deployment is significantly higher than in the past few decades and the visibility is much higher as well.
Edit:
There is a flip side to this coin. When you have a systemic problem of this scale, you should be cautious about making simplistic (especially moral) judgements about individuals in the system. When someone's training, incentives, position in the community and even equipment nudge them towards bad actions, even decent people will routinely do bad things.
"There's a reason you separate military and the police. One fights the enemies of the state. The other serves and protects the people. When the military becomes both, then the enemies of the state tend to become the people." - Commander Adams (Battlestar Galactica)
Obviously, this doesn't directly address the militarization of the police, but it should be easy to see how it can go both ways. Outfit the police as a military unit, and they'll start acting like one. How much surplus military equipment was sold to police since the Iraq war?