Who were these US pilots that were so fearful of a tail rotor failure?
Probably not pilots, RUMINT is a specialty of all branches of all militaries. Someone somewhere had a tail rotor problem and a resulting prang, as the story(ies) grew amongst non aviation types in assorted bars over years it becomes common knowledge that any problem with "X" is instant disaster. Pilots are helpful by pointing out that sky gods like themselves can deal with it while lesser pilots without their superior skills/training/ego can't.