The amount of people who support this in this thread really astonished me, and made me feel sad.
When I was younger, my parents would take my sister and I to Disney World every couple of years. We come from a middle-class family, but my parents didn't make the amount of money they should have for how hard they worked.
The only way my parents could afford to take my sister and I was by watching how we spent every penny on our trip. We drove instead of flying. We'd get 4 day passes for a 10 night trip. We'd borrow a tiny, 40 year-old camper from my grandparents and stay at Fort Wilderness for $50/night. We'd spend a lot of time doing "free" things like Downtown Disney or resort-hopping.
One of the biggest money-savers was bringing our own meals into the parks. It wasn't like we set up a picnic blanket or anything. The four of us would sit on a park bench, and eat our cold-cut sandwiches while we watched more privileged kids running around with Mickey ice cream bars and souvenir popcorn buckets.
It doesn't seem like a lot, but doing an entire day in a park, our family of 4 would save $70-$100 per day. To take that away and have everyone say "that's okay", yet when ticket prices go up $20/day and everyone losses it; dumbfounds me.
I suspect if you already purchase your meals in the park, taking this away doesn't affect you and so you're okay with it. I get that.
Just try to remember some people are already stretched so thin visiting, and bringing your own meals is a HUGE expense saver.