It's extremely vital that there are restaurants and food manufacturers that have nut free foods prepared and packaged in a nut free environment.
They are the only products that people with nut allergies can count on, especially children.
By having nut free foods, McDonald's provided some confidence in parents that their children could safely eat there.  Now that is gone.
Maybe they are better off in the long run.  Food prepared at home is much healthier than McDonald's anyway.