I'm fascinated by the level of pure speculation being voiced by so many. There is so much that we do not actually KNOW.
Here are some dumb questions:
What exactly constitutes "clear of the taxiway"? Does that mean that no part of your aircraft is physically within the confines of the taxiway? Does it mean that you are also clear of the adjoining "grass" area [between ramp and taxiway]? What about the service road, is that included as well? Does it mean that 100% of your fuselage is within the ramp area?
Does the wingspan of the A380 fit within the confines of the taxiway? Does it extend beyond the limits of the taxiway; if so by how much does it overlap? Is it 1m, 2m, 3m, maybe more? If there is any overlap at all; does that mean that the A380 is never within the confines of any taxiway? Of this particular takiway (A)? What exactly constitutes being "on the taxiway", or within the taxiway? Does that mean ALL of your aircraft, or only certain parts of it? Which parts?
Is the crew of [in this case] the Comair jet expected to assume that even though its aircraft may be clear of the taxiway physically, it is possible that a A380 - whose span happens to extend beyond the confines of the taxiway - just might be passing behind it and therefore it must clear by enough to accomodate the A380? How does the Captain determine just how much is enough? Is it 1m, 2m, 10m?
Is it possible that the pilot of the CRJ could have backed up into the wing of the A380? Why didn't the pilot of the CRJ anticipate that an A380 might want to pass behind him?
Why is the A380 restricted from using Taxiway B? Is that because its wing span overlaps the taxiway by enough to cause a hazard on the adjacent runway? Did someone decide it was better to risk a collision with something on the ramp as opposed to something on the runway?
If there is nothing particularly unusual about this aircraft (A380) that constitues significant hazard while it is moving about the airport, then why all the special restricitions and limitations (pages long) about where it can go?
Are the pilots of other aircraft types expected to make special allowances in their own operations for the unusual nature of the A380's size, or does that responsibility rest with the pilots of the A380? Is it the responsibility of the controllers? The airport authority?
Unitl we KNOW the actuall FACTS that lead to this incident, attempts to shift blame around appear to be a waste of time.
The only thing we KNOW at this point is that one of two aircraft collided with the other. Let the experts decide which, why and how; after which you can crucify the culprit(s) of your choosing.