While I can understand your frustration, it's important to note that dishwasher detergent manufacturers do not generally promote the idea that you can load heavily soiled dishes into the dishwasher without any pre-rinsing. The claim you mentioned seems to be an exaggerated or misinterpreted marketing statement rather than an actual recommendation.
Dishwasher detergents are designed to work most effectively when they can come into direct contact with the surface of the dishes. However, heavily soiled dishes, especially those with dried-on or burned-on food, may require pre-rinsing to achieve optimal cleaning results. Pre-rinsing can help remove large food particles and prevent them from clogging the dishwasher's filter or affecting the cleaning performance.
It's important to follow the dishwasher manufacturer's guidelines and the recommendations on the dishwasher detergent packaging for best results. These guidelines typically include pre-rinsing dishes to remove excess food particles.
However, advancements in dishwasher technology and detergent formulations have improved their cleaning capabilities, making them more effective in removing various types of food residues. Modern dishwasher detergents often contain enzymes, surfactants, and other ingredients that help break down and remove tough stains and stuck-on food.
It's always a good idea to scrape off excess food from dishes before loading them into the dishwasher and to follow the dishwasher manufacturer's instructions and the detergent's recommendations for optimal cleaning performance.