Well, that's just another reason not to eat at McDeath's.
If you have a food allergy, or have food choices (like being vegetarian/vegan) your best bet is to not eat out very much and to prepare as much food from scratch as possible. It's really the only way that you can really know what is in it.
Restaurants are supposed to disclose all their ingredients, but I doubt that few do.
I'm sure they only made the claim to boost sales. What do they have on their menu that isn't unhealthy in any way?
I also had to chuckle at the cnn report where one lady (who says she doesn't eat any animal products) is suing because she found out that the fries have dairy in them. I thought it was a fairly well known fact that they use beef stock as a "natural" flavor. So, now that she knows it also has dairy it becomes an issue? It's not like McD's cares about vegetarians/vegans. Why would somebody who is against animal product use support a place like McD's anyway?