What's the story with the protestors

Restaurants on Plaza Peru in Concepción, Chile were serving beer for lunch, but about 20 feet away almost 15 protesters with face masks were serving molotov cocktails, and tire fires on Monday at about 1 p.m.
The protesters began their demonstration by piling about 20 tires in one of the traffic lanes of Calle Chacabuco, and setting fire to them with a loud crack as a bottle filled with gasoline hit the pavement.
The protesters continued pouring lighter fluid on the fire as well as running up to police tanks and throwing the molotovs in their path.
One of the cocktails missed the police vehicle and hit a pillar of a nearby restaurant. The bottle exploded in front of a kiosk selling newspapers and snacks, and according to a local newspaper, La Estrella, lit the pants and socks of a bystander on fire.
There were about 50 people on Plaza Peru in the surrounding restaurants and walkways. Some were walking to class at the University of Concepción, which is on the other side of Calle Chacabuco, and others were eating lunch.
The demonstration happened outside the doors of the art building on the university campus.
Most people stopped to watch the protesters, and were walking back and forth under the portals of the restaurants trying to avoid any contact with the molotov cocktails.
Shop owners pulled down the metal coverings for their windows and closed their shop doors.
The police tank, which is permanently parked on the corner of Plaza Peru, moved to the side of the plaza to squirt water from a hose attached to its roof to extinguish the fires from the molotove cocktails.
As the police tanks approached Chacabuco a protester ran up to the tank, and threw a flaming bottle at the wire-protected windshield. The tank sprayed the protester and the burning pavement with water.
After about 10 minutes all the protesters dispersed onto the university campus before any of the police could follow them.
The protest is most likely an effort to call attention the Mapuche hunger strike that has spanned the last 85 days.
The hunger strike is in response to a law that was created in 1985 under Augusto Pinochet. The law has jailed about 35 Mapuche political prisoners in different Chilean prisons due to its enforcement.
Many of the Mapuche people have gone to jail because they retaliated against the unfair prosecution of their people, and the misuse of their land with demonstrations, vandalizing and arson. In some cases it was against companies that have built businesses on their land, as well as desecrated sacred cemeteries with deforestation and mining.
The antiterrorist law allows people who commit various crime, such as arson or hijacking of a public transport, to be held in prison for up to two years without a formal charge, and can be sent to prison based on anonymous tips.
The Mapuche have asked the President of Chile, Sebastión Piñera, to change certain articles of the law, such as allowing anonymous tips, but he has not made any efforts to change the law.
While it was not clear that this was the reason for the demonstration it has been a sensitive issue for the almost one million Mapuche people in Chile, as well as Chileans in general.
The hunger strike has drawn international attention from the Human Rights Watch, and people such as Noam Chomsky. Chomsky wrote a letter to a prisoner expressing his sorrow for the suffering of the Mapuche people, and his disapproval that Piñera was unwilling to hold talks and repeal the law.