So did the ancient Greeks. If a city-state was under siege, it only took one person to give the attacker access to the city, access that lead to murder, rape, and enslavement. It has always been the case that one person can do an astonishing amount of damage. Just as one person can do incredible damage, so each of us is vitally important in creating a safe, caring place for everyone. Each action we take is important.
Ethical behaviors strengthen community.
In times past, the strength of a community met the needs of many an angry person, many a desperate single mom. Community meets OUR needs in desperate times. Community is sacred because without community, we are nothing. Community is the sine qua non - that, without which, nothing.