At root, many modern conveniences were not developed for people’s needs, but for the Industrial Age. Your automatic dishwasher was not designed for cleaner dishes, it was designed for automatic dishes. You have become used to washing the food off them before putting them in the dishwasher, precisely because it can’t clean dishes as well as you can.
Goodness me, you’re right! Though now they have superheavyduty ones, that don’t require pre-rinsing.
But that just seems nasty to me. : )
Mike