I understand their logic to a point. After the Canes game they felt that the franchise was humiliated. The GM left in disgust, the Leaf faithful gave the zamboni driver a standing O, he made rounds in the media, everyone laughed at the inept Leafs.
Seeing this, the GM probably lost faith, as possibly did the owners in Dubas. Who knows? Ultimately they clearly decided "no more spending". If the Barrie trade worked, fine, if not, we ride it out. That game, in the fashion it went coupled with the other two bombs against vital opponents in the same week, convinced them to not risk anything more.
Even as I understand the logic and I think the loss to the Canes might be good for Leafs long term (one way or another), I still think when you're on the bubble you make some tweaks and try and improve what is a glaring weakness. Getting in and losing is still better than not fighting for it. The team still has to do all the work, whether it's with a green D or some depth.