The reason why reasonable people often associate the Tea Party movement with violence is because Tea Party members and ‘spokespersons’ often embrace violent rhetoric and displays. As I am sure you know, the original Boston Tea Party incident was a non-violent protest action. However, the modern-day Tea Party as a whole eagerly embraces calls to violently overthrow of the federal government. The fact that it grew out of the same networks that fuel the Minuteman and paramilitary militia groups in this country (whose members brag about shooting illegal immigrants and have conducted high-profile terrorist operations and killed innocent U.S. civilians, respectively) adds to this impression. So does the fact that many Tea Party members bring firearms to public events.
Reasonable people in the U.S. at this moment in history are and, frankly should be, much more concerned that Tea Party members are willing to physically hurt people to accomplish ideological aims than Occupy protesters.