How is it bad publicity? Baseball games get called on account of rain all the time and its reputation is no worse for wear.
And the loss of revenue is only really going to hurt those teams getting revenue sharing, and probably not a whole heck of a lot. Much of the WC classic merchandise is purchased before the game.
Money spent advertising is down the drain as well, and I'm sure that's quite a bit. Honestly, I don't know how it could result in bad publicity, but the media has their ways of spinning things. The Classic getting cancelled is good for no one.