George Will is a huge and longtime fan of the CUBS, not the Nats.
Kraut was a Orioles fan, but switched allegiances when the Nats moved to D.C.
Will has been a fan of the Orioles, Senators, and now Nats, and yes, the Cubs are a guilty pleasure, however, he is a (or has been) a minority owner/director of the Orioles and Padres. To say he is exclusively a "Cubs fan" is a bridge too far.
All the more reason to hate the Cubs.