RL Army Pilot here. You still have some TRQ even without the engines running, caused by other small factors like resistance or friction in drive components for one. But the resistance caused by aircraft body and vertical stabilizer is enough to counteract that small force. To say it is not hard to coop with tail rotor failures is a bold statement. If the conditions just happen to be in your favor, you have a chance. Most times the tail rotor fails at a bad time. Just study a few helicopter crash investigations and you will see that. Loss of tail rotor is often a violent event. 60's can't out run the loss like other aircraft, and if Huey's loses any components, their CG shifts and the helicopter noses over. I am not saying your wrong, but most of the time tail rotor failure results in catastrophic loss of the aircraft.
http://www.navytimes.com/article/20090209/NEWS/902090332/Families-sue-Seahawk-maker-fatal-crash