I think that most crew when faced with a serious incident would consider using another airfield but in this case with both engines in trouble, and one on fire by all accounts I can picture the ECAM workload must have been utterly bewildering. In such a circumstance it would hardly be surprising if they were to dismiss the thought of diversion almost instantly as too much extra work and revert to the traditional assumption that we brief on every departure, to turn back and re-land where we started from.
Go back to the audio of Sully setting up for the Hudson landing. He's so maxed out he can barely spare the brain cells to speak coherently, and then so briefly it is not readily apparent what he means and on one or two occasions doesn't have the capacity to reply to RT calls - if he even registered haring them. That's the reality.
Beating the guys up for not thinking about STN which was very possibly just as close and might have been self-evidently more suitable in a simulator exercise is to ignore the overwhelming pressure they were under just to contain the situation and LAND IMMEDIATELY. They're only human after all.
Perhaps this incident will strengthen the argument for pilotless aircraft as a computer would clearly have handled all this better...
Wouldn't it?