I don't think this is true.
League-wide, teams have won by 3 or more goals 39.0% of the time. Using that percentage over 39 wins would suggest 15.21 of Edmonton wins should have been by 3 or more. Edmonton has won by 3 or more 12 times
League-wide, teams have won by 4 or more goals 16.15% of the time. Using that percentage over 39 wins would suggest 6.3 of Edmonton wins should have been by 3 or more. Edmonton has won by 4 or more 7 times
League-wide, teams have won by 5 or more goals 4.95% of the time. Using that percentage over 39 wins would suggest 1.93 of Edmonton wins should have been by 3 or more. Edmonton has won by 5 or more once.
Edmonton doesn't blow out teams more often than average in general. In fact, 46.3% of all their games have been decided by 1 goal where the league average is only 38.3%.
Oddly, on average teams win by 3 or more goals more often than they win by 1 goal, whereas Edmonton has 18 wins by 1 goal and only 12 by 3 or more.