Perhaps instead of who is at fault we can ask " how do we prevent this from happening again."
A) If you park on a helipad you have to expect other helicopters to arrive so secure your a/c. If the door is not in your hand it should be closed and latched. If not starting the tiedown should be on.
B) If taxing near other a/c get as low and I mean low ( 6 inch hover ) as possible as far away as practicable, then taxi in. This reduces downwash a great deal.
C) If at a refueling point don't refuel and beetle off for lunch blocking access to the pumps. Move the aircraft.
D) Look around.
E) monitor TWR or other local freqs to get a picture of incoming traffic - perhaps delaying or accelerating your start a few minutes will avoid a problem.
F) Remember airmanship is not the boat you arrived on.
Perhaps a large sign with the statement - " Unforcast Winds of up to 100 Miles a Hour from any direction can be Expected in this area!" should be posted?
I once had the great joy of landing near a parked 206 on a small pad with 10 other helicopters coming and going.
A fellow had removed the tail rotor drive shaft cover layed it on the ground and then gone into the hangar to get some tools.
Needless to say the drive shaft cover ended up around the skid gear of the 206.
Was it my fault ? - Well, I did not spot the cover on the ground but would you leave a cowling on the round in a place where there is a helicopter landing or departing every 10 minutes and expect not to have it damaged?