Why do bees sting and they die?

In some bees, their innards are attached to their stinger, which is barbed and is supposed to stick in the victim's skin. When the bee stings you, it releases the stinger from the abdomen along with some vital organs, causing the bee to die minutes later. This does not usually happen with hornets. They have a smooth retractable stinger that is meant to inject venom into the victim's body, not stick into it.