Placing a whole pizza or other food item in the dishwasher is unrealistic - not many, if any people would manage to put that much soil on dishes. When dealing with such a mess, isn't is obvious that the filter will get clogged?
Washing a more realistic load, with soils of varying types (proteins, tomato, grease, fine particles) is a far better way to test the performance of a dishwasher. In this case, the (hopefully) high temperature will disintegrate larger particles of food, where they are collected in the filter, and typically flushed away by the wash arm.
The filter then self-cleans furthermore during the drainage cycle.
Given the reports of barely tepid washing temperatures in American machines, is it little wonder the filters might be more prone to clogging? The high temperature action found in European machines, as I said before, helps to disintegrate the largest particles into mush (soup), which can be safely flushed away. Of course, insisting on short cycles and low temperatures won't help.
That said, however, our resident member Frigilux (Eugene) has clearly demonstrated there is no issue with using filter machines on very dirty loads. He has reported no significant collection of food stuffs, if at all on the filters on his recent GE machine.
In my own experience, using the shorter, cooler cycles does result in additional buildup within the filters of the DishDrawer. While dishes still come out clean, it may not be particularly reassuring if you don't pay a lot of attention to the filters. Using longer, hotter cycles frequently seems to prevent buildup, and this seems to parallel what other members with these machines have suggested (or members whose machine's programming features high temperatures and 1-2 extra water changes by default).
