I admit, I sympathize with the "silent lunch" (and breakfast and supper) thing. I put in a lot of time and effort making meals, and I really wish everyone would just close their mouths and chew their food!
As opposed to throwing it around the cafeteria.
I don't get those opposed to it, especially if the kids get to go outside after lunch.
I've seen too many kids just talk during lunch and not eat (my son would be one of those types of kids).
Let them eat in quiet for 15 minutes, and then let them get their energy out running around on the playground.