Vegetarian diets cruel for dogs?

I think this depends...for some animals its necessary b/c they have allergies to other animals proteins and in those cases its not at all cruel, think if that animal was in the wild and then found out from eating meat with its pack it was getting sick. I'm sure they would have no idea what to do, and its b/c of the veggie diets that these animals can survive better then if they were on their own. But in all other cases I don't think its a good idea. Animals need protein which comes from the meat that they eat.. Ya sure they can eat soy based crap..but its not the type of protein that they need for their body's. Also they will be missing other types of mineral/ vitamins that they need like omega's and amino acids.