Even a slight foot forward, which won´t move or turn the helicopter will produce quite a lot of wind from the big fan at the back.
Understandable now?
I quite understand what you are trying to 'mansplain' to another helicopter pilot BUT a wheeled helicopter like an Apache will turn with very little pedal if the tailwheel is unlocked and, since they appear to have been waiting to line up on the runway and would ground taxi to do that, it is extremely unlikely that the tailwheel would be locked again and even more unlikely that they would sit with pedal applied and the tailwheel locked.
Yes, a TR will produce thrust on the ground but in the scenario posted by the FW pilot - the turbulence he experienced would not have been due to the helicopters.