Years ago, I enjoyed reading through my parents' Q&A Legal Info book, which gave legal advice to people in hypothetical situations. One of the scenarios involved a burglary and asked "Can I shoot a burglar who is looting my house?" According to the book (which was written in 1985), it is illegal to use deadly force to protect even the most valuable property. Only when the safely of your life or your friends/family's life is threatened can you use force and claim self-defense.
With the recent Argentine revolution we have seen police using potentially lethal force against workers occupying factories. These activities are in a direct violation of the law "No force to protect property," so why do the police do it?
Simple. Because there is no way to stop the workers' revolution short of forceful suppression. If there were no police brutality Argentina would have gone socialist long ago. But since the only way to prevent socialism is to blockade workers' efforts, then you get the mess we see nowadays.
Remember folks: The people in power have no reservations on nixing existing laws if they will keep the elite in power. Property ownership and control is the bourgeois' weak spot and you can see how fervently the po-po's have been protecting that weak spot. It is important that revolutionary-minded activists discover their own weak spots and reinforce them as well. After all, you can't attack a tank with a toothpick.