At the grocery store I only see "MSG Free" labels on soy sauce, ramen, noodles, etc. but nothing for chips, burritos, burgers, etc.
I know there are people who dislike MSG, but the MSG scare was also racist scaremongering, and I wonder how many people think they dislike MSG because the media said Chinese food will kill them while gulping down a big mac and bag of doritos every day
Maybe that type of packaging is for people who are trying to shop for others. I know I have a friend with a gluten sensitivity so I try to buy things for him sometimes and honestly having the "Gluten-Free" label on things that would never have contained Gluten to begin with is sometimes helpful, I would imagine even more-so for someone who is doing that type of shopping for someone else for the first time.
The number of posts I've seen where the friend/boyfriend/whatever is like "omg, I didn't know X was in thing-that-requires-X!"