Crates: Dog/puppy abuse?

Why is swatting a dog on the nose or rear end for misbehaving considered abuse, but stuffing your dog in a crate for hours at a time considered a great thing? At least the swat only lasts a second and it does teach the dog not to chew things, get into the garbage or go potty in the house. Leaving your dog in a crate while you're at work all day just seems so mean, dogs need to move around and play. Not lay around in an over sized Tupperware container. So, why isn't it considered abuse?