"The fact that you can't see a shimmering pool of fuel under the aircraft doesn't mean it isn't there"
There was a blazing fire on the wing.
How could they have established if the runway had fuel on it? Would that have made the evacuation more or less urgent? How could they decide? How long would all this have taken?
Your comment is seriously over-complicating this, and over-estimating the number of variables any crew could reliably deal with.
The only had time to deal with the actual known problem "wing on fire".
They didn't deal with it.