I feel your pain, but their explanation of the problem is correct. On a Fixed Pitch Helicopter to avoid what is commonly called the "Death Wobble" two things need to be done.
1) You MUST advance the main blades slightly in the direction of rotation, about 1/2"-3/4".
2) The main Blades MUST be kept equally tight or drag will cause one or both to trail back, causing the wobble again.
As to for every single Heli being test flown, come on you didn't REALLY believe that did you?