This is what I think:

If BJ release Undivided as a single, the people who hear it are going to think that BJ thinks that the people responsible for September 11th are also connected to the Iraqis and Hussein's 'evil' regime. They will think that BJ think that everyone is united over this 'war' and see the song as a piece of American patriotic bullshiit.

That is if anyone took any notice of it anyway, which the probably wouldn't.