Anarchism has always been a philosophy of mutual aid, freedom, cooperation, dismantling illegitimate hierarchies, and moving towards open democratic structures in all aspects of life. Generally speaking, the people at the top of the illegitimate hierarchies, like people who command countries because they were born to the right family, or people who command workers because they have a piece of paper saying they own the factory, well ... they do not care for this philosophy. And the police are on their side.
In every society, those in power will always call the people who are peacefully trying to change the system "violent anarchists" and the people who violently enforce the system "peace keepers". Violence, to them, is having to give up their vacation home so someone else doesn't have to be homeless. Peace is having the police beat up and jail the homeless people who are sheltering there to stay out of the cold. To those whose privilege is built on mountains of injustice, merely asking for justice will be called violence, and violence to protect their privilege will be called justice.
Do not be fooled. The police does not enforce justice, they enforce privilege, property, wealth, and power.
Black Lives Matter.