“[Berkeley authorities] were going to allow it to happen until they determined that it was too dangerous for it to actually happen,” the black bloc member said. “So what other choice did we have?”

Berkeley put the blame for the violence at the Yiannopoulos event squarely on the black bloc faction, which campus police said numbered 100 to 150 members. . . .

Videos show black bloc members using firecrackers as a shield to get close to the Student Union, where they pulled down barricades. They took turns whacking at its windows with their sticks, rocks and the crowd-control barriers themselves. The bulk of the blows were directed at the Amazon store. Videos also show black bloc members tackling and assaulting Yiannopoulos supporters.

There is a strategy behind much of the smashing, according to interviews and published manifestos. The bloc pushes back against police lines, opening and holding space for mass demonstrations as police seek to corral and disperse the crowd. They draw pepper spray, rubber bullets and other uses of force. They say they focus destruction on standard-bearers of capitalism: Bank machines and a campus Starbucks were hit after Berkeley called off the Yiannopoulos speech.

“Starbucks is a symbol of global capitalization,” the black bloc member said. Those activists interviewed expressed no remorse for the property damage. They said it should pressure the university to think twice about allowing such events in the future. They hold the same regard for violence against people.