The question I would have for any pilot, is why would you NOT deice in a situation like this?
"Getthereitis, Gethomeitis, Completetripitis."
Sadly this phenomenon has killed many highly experienced veteran crews operating perfectly good aircraft.
It's shocking and makes the situation all the more tragic. Reports indicated that over 3 feet of snow had fallen in the area and that temperatures were below freezing. Considering they were flying in a small plane in less than satisfactory flying conditions, why play with fire?