Well, we pilots all know that most of the time, you could easily go even with some snow or other contamination on the wings and you wouldn't crash. The keyword is "most of the time".
If they would have an engine failure, some windshears or any other unforseeable incident, "some snow" could easily aggravate the situation. That's why we do these calculations and do these de-icing procedures all the time.
Just because it worked this time doesn't give you the insurance that it will the next time.
It's not only playing with the lives of the passenger and crews on board, but also with all the people living under the departure route. I think it's unforgivable that airport authority doesn't intervene in such situations. Maybe it needs another crash until they will do.
Dani