I think the issue is when you look at the teams the Leafs play and the numbers of PIM/G and oPIM/G they have and how that number shrinks to lower than season average when playing Toronto. Just look at these numbers from the past 5 games:
BUF- (season avg) 7 PIM/G, 8 oPIM/G actual game TOR 10 PIM/G, BUF 2 PIM/G
MON-(season avg) 9 PIM/G, 8.7 oPIM/G actual game TOR 8 PIM/G, MON 4 PIM/G
WSH-(season avg) 9.5 PIM/G, 9 oPIM/G actual game TOR 8 PIM/G, WSH 6 PIM/G
STL-(season avg) 8.3 PIM/G, 8.5 oPIM/G actual game TOR 6 PIM/G, 0 PIM/G
ARI- (season avg) 7.5 PIM/G, 8.3 oPIM/G actual game TOR 2PIM/G, 8 PIM/G
In 3 out 5 games, the opponents PIM/G is less than half their season avg.