Because Detroit is located in the "West."
"To these onlookers, this is one of the problems with the NHL's unbalanced schedule. A team, like Detroit, playing in a division with Columbus, St. Louis and Chicago, has an unequal access to easy points.
And what do the numbers say?
Well, against the Jackets, Blues and Blackhawks, the Wings compiled a record of 21 wins, one regulation loss, one overtime loss and one shootout defeat.
So in 24 games against these three Central powderpuffs, the Wings didn't pick up at least a point in only one contest.
Overall, of a possible 48 points available, the Wings acquired 44.
Against the other member of that division, Nashville, the Wings were also successful, winning four, losing one in regulation, one in overtime and two in shootouts.
In sum, of a possible 64 points in Central Division play, the Wings picked up 55 points."
This is from Damien Cox's blog (sports guy at the Toronto Star)