I am not exactly sure why anyone thinks this has anything to do with giving an FU to the Leafs or Dubas.
It took him until his contract year, and two years of doing things which were the direct reason for the Leafs moving him in the first place, to finally get it right.
If anything, our fans should stop trying to constantly trade our star players for non-star players, because Kadri was less of a star player than any of our current star players, and did a lot more things which warranted moving him than any of our current star players, and we got a strong return for him (something we would not have got based on his two prior seasons with Colorado), and people are still whining about it.
No coincidence that there there is a strong overlap between the whining and the impatience too.