It occurs to me that arm chair judgements might be better tempered by consideration of the time line in which the actual events occurred.
It is possible that the decision to perform an emergency evacuation was done in a proactive manner, as well the in-process decision to reroute passengers to overwing exits.
As time progressed and the ground emergency folks determined that the risk was suffciently mitigated, they again rerouted some passengers from the no longer needed but less agile evacuation route of the wing back into the cabin. Somewhere along the line I'm sure that they neded to get ground emergency folks into the cabin for better assessment (hence a need to clear the aisles of confused passengers).
I'm not saying that all this happened, but at least it keeps me from making harsher and possibly unwaranted judgements.