Let's get one thing straight, shall we.
Vandalism is not equal to, the same as, or even remotely like, violence. One is damage to property, inanimate objects that have no feelings what so ever. One is damage to people.
Graffiti, which may be the oldest form of political expression being that it is at least 2000 years old, is just that, political expression. Even when it's just some kid, who is probably not old enough to vote, leaving his or her tag on a wall somewhere. I love graffiti. Graffiti is not violence.
Window smashing, while scary and loud and full of breaky glass, is not violence. It is property damage.
Property is theft, and pardon me while I quote the Marquis de Sade: "Tracing the right of property back to its source, one infallibly arrives at usurpation. However, theft is only punished because it violates the right of property; but this right is itself nothing in origin but theft."
In order to get the elites to release their stranglehold on the rest of humanity, the elites must scared. Yes, scared. That's an ugly truth, but it is truth none the less. And to scare them without committing acts of violence means that they must be afraid of something else, loss of property. And they should be afraid of that. They should be shaking in their boots, unable to sleep at night, haunted by the ghost of Jacob Marley in the wee small hours telling them to repent.
We know what violence looks like at the Occupy sites. It looks like cops pepper spraying young women behind a barricade. It looks like war vets getting skulls crushed and spleens lacerated by "non-lethal" weapons. It looks like douchebags rapists who rape women in tents. Violence causes actual harm to the bodies of actual people and is generally performed by those with power over those with less.
Vandalism is acts of destruction done to pieces of property done by those with less to property owned by those with more.
These things are not the same, and should never, ever be uttered in the same breath as if they were.