The "may contain nuts" warning is a common legal cover to prevent lawsuits. It is used even where the presence of nuts is unlikely. McDonald's has a low-price mass market business model. That choice is their right. They should not be required to serve special needs niche markets. If you can't eat at McDonald's, eat somewhere else. 

McDonald's blunt announcement may be another sign that we've entered a new age where tails will no longer wag dogs. In that spirit, it's time for the media to leave SJW whines and campaigns in the Twitterverse where they belong. Let's have more stories of majority interest.