The Cubs are mostly owned by the Ricketts family, which is staunchly GOP/pretty conservative, including the gov of Nebraska, Pete Ricketts.
The team may have elected to go to WH now, just to avoid some future anticipated protests, such as those that have discouraged many entertainers from accepting gigs for the inauguration.
More likely that delaying a visit to the WH would interfere with spring training that will be starting in February.
Obama invited them. This is a non story to me. IDC what pro team refuses to stay away. The media think people are hurt over celebs and pro jocks refusing to meet with Trump or refusing to perform for him. These people hold no power over the American voter when it comes to real life.
When the POTUS invites you to the White House for a nonpolitical function, you go.
I think the Cubs are just trying to stay classy here.