I certainly will not force my children to grow up liking a particular team/company just because I or my family likes them. I would hope that I would teach my children to appreciate a well played game (or well run company) and make the appropriate choice for mature reasons. I would also hope I would teach them that you do not need to have devotion in the face of mediocrity.
One has a choice in who one roots for and one should use proper reasoning when coming to that choice. Rooting for a particular team/company should not be a mindless activity.
Be a fan of excellence.