According to the essay "Everyday Life," why were citizens of Massachusetts and other states so alarmed by the skirmishes of Shays's Rebellion?

The battles between rebellious farmers and government militias alarmed many citizens of the young United States because the United States had so recently fought the Revolutionary War and was still recovering. Many of the soldiers fighting for the Regulators and the government militias had fought together during the Revolutionary War. The fact that the fighting occurred between different groups of US citizens was shocking and surprising.