Likely because folks who scrimp and are not on foodstamps get angry at folks who get food stamps and don’t scrimp. Ive had the same feeling being at a grocery store and seeing someone with foodstamps buying items that I can’t afford and had been tempted to get. If foodstamps where universal it would likely mostly get rid of this feeling. I mean folks like me would still scrimp to save money for things but since we would be getting the same food allotment it would not feel like we were being looked over for our life needs. That being said it would likely lead to more food stamp selling type of thing although that is great for scimper folks who would let go of cash to get more or better groceries.