The President also managed to slip in a subtle shot at the Leafs saying, "I like your hockey teams, except the Leafs," simply because the Leafs beat the Flyers in January, pushing their record to a perfect 3-0 against the Flyers this season. If Biden doesn't like the Leafs for that reason, than he probably doesn't like any of the other teams in the league this season aside from the 3 or 4 that haven't beaten the Flyers.
As disgruntled as the fans of other teams get and say "it's always about the Leafs," it very clearly is always about the Leafs if the President of the United States mentions them too. Luckily for Biden, the millions of Leaf fans he just dunked on can't vote against him in the election.