Lawsuits. Many grocery stores now have sealed dumptsers with electric crushers inside to destroy and compact everything inside. Dented cans may sometimes have pinholes in the creases which can allow air molecules to spoil meat/grow mold. Yes, I remember the day old bread/donut days and the dented can displays.
They even crush the boxes so you have to go out and buy a new box. If the EPA really wanted to do some good, they’d start at the re-use point.