Then these "Experts" should know that it is far more efficient to accelerate a large amount of air to a low speed, then a small amount of air to a high speed, as well as the noise. Compare the noise and downwash disturbance from a 5-ton helicopter (S-76) in the hover to a Harrier jet.
And their claim to hold degrees from a particular university is far outweighed by my degrees and doctorates from Snotgobbler University, Noo Joisey, they cost me $50 each.