I agree that the lack of water and other refreshments is a bit poor, but I do not think I would be too upset with other aspects of the situation.
You do not know for sure that the aircraft had 'full fuel' either, and to speculate based on the fact that it took a long time it took to refuel is, to me, not sufficiently reliable.
Weather, especially fog, can come and go very easily. For all you know, if BA flight had departed for GIB again, it may have had to come back again, causing further delay. Just because one airline got in, it does mean the another should have got in, because things change.
I think you have just been exposed to one of the less pleasant aspects of air travel. It's often unavoidable. Bear in mind that airlines want to avoid these situations as much as you do, maybe even more so.