I agree, but telling an overworked parent because their dishes are dirty because they didn't take the time to deeply understand the mechanism of their appliance doesn't tend to go down well.
If a machine doesn’t function correctly or well, then fixing it requires blaming some part of the system that can change for the better. The dishwasher cannot change; it’s just a machine. It could be replaced, but that might be expensive. Much cheaper for the operator to change what buttons they press on the dishwasher instead.
If that requires reading a manual, or carefully timing the actual length of each wash cycle, or making a recording of each of those wash cycles so that you can work out how long they fill for and how many pre-washes and rinses that they each do then so be it.
If a machine doesn’t function correctly or well, then fixing it requires blaming some part of the system that can change for the better. The dishwasher cannot change; it’s just a machine. It could be replaced, but that might be expensive. Much cheaper for the operator to change what buttons they press on the dishwasher instead.
If that requires reading a manual, or carefully timing the actual length of each wash cycle, or making a recording of each of those wash cycles so that you can work out how long they fill for and how many pre-washes and rinses that they each do then so be it.