The problem with the grain free foods that are causing health issues, is that while they are grain free, they rely way too heavily on non-meat products to make up the bulk of the food. Literally taken from an article this year on the subject: "The common factor was a diet heavy in peas, lentils, chickpeas and potatoes — carbohydrates typically intended to replace grains."
People need to actually EDUCATE themselves on a dog's nutritional needs and how to understand a bag of dog food. Most people listen to hype. The trend lately is "grain free is the best for your dog!" So people grab a bag of food off the shelf because they read grain free on the front. Flip the bag over and read the actual ingredient list. Dogs are omnivores, but definitely heavier on the carnivore side obviously. A dog food should absolutely NOT have a starch OR a grain as a main ingredient. If potatoes or lentils, etc. are listed within the first few ingredients, turn the other way and find a better food. Absolutely they can and arguably SHOULD be in the ingredients - they need fruit and veggies, and even grains aren't really bad, as long as it's in moderation. They need MEAT.
Grain free is certainly a great option for a dog food as long as you put some research and education into it as well. The research isn't showing that ALL grain free foods are causing issues - just the ones with non-meat items as the primary ingredients. Does it really make sense that a dog should be eating a diet made up more of potato and peas than beef or rabbit? Honestly, if it's grain free and cheap, or cheap-ish, I'd stay away. The price tag will be a good indicator that they're using something other than meat to fill up their bags.