Once again i think this may be a discussion that comes down to semantics.
First of all what are we taking Alleviat(ion) as:
1)To reduce severity off.....
2)To Remove.....
In the case of 1, I agree entirely in that there are systems available and in place in many aircraft that Alleviate the severity of events that cause instability of aircraft. This is demonstrated in the aircraft that you reference and alluded to in the references you have sighted.
However in the case of 2, I know of no such system that can entirely remove the effect of a disturbance. When i read IO540’s statement “counter up/down draughts which the aircraft encounters.” I took it to mean “Remove”
So perhaps this is the reason for a little dispute?
In response to your question on harmonic dampening principles. It is the same as ANR in headsets or any other waveform for that matter. By adding the opposite input, of what is currently being experienced, to the system a Null result can be achieved.
I refer to it as dampening because (and this is now talking specific to an airframe now) the input that introduced is often less the initial disturbance so as not to exacerbate the situation. The Disturbance will gradually get smaller and small till it is nullified or removed all together. The best way to think of this is like a dynamically stable aircraft.
I hope this clears things up...and do apologise if my language sounds abrupt, as English is not my first language