Any machine with an electric motor needs overload protection, but most overloaded machines will struggle to comlete the cycle, however imperfect the results might be. Jeff was called to service a WP machine in a house rented to students. The machine was pulled away from the wall at an angle. Trying to figure out what had happened, he restarted the washer. What he discovered was that the machine was packed with three baskets of laundry and with each stroke of the agitator, the whole machine jerked from side to side on the floor because there was no other way to diffuse the motion of the agitator. He showed the property manager that, even wet, the load filled three laundry baskets. It was not even a coin-op machine, but some lazy kid who must not have had any experience in taking care of himself, who could not even do laundry. Once emptied, the machine still worked. The landlord said the service call would be charged to the oaf responsible.
I have seen front loaders packed so full that no tumble action can be observed, but they complete the cycle without going out on overload.
Contrary to Spinspeed's assertion, this is not a debate about TL vs FL machine performance. The poster posed a real question about soap and scum residue left on clothes and that is more a problem of what the machine has to cope with regarding water conditions, load size and additive dosing. If the machine is properly loaded, the water properly softened and at the right temperature and the proper amount of detergent is used, added properly and allowed to dissolve, any top loader I have used produced laundry that was very well washed and rinsed so that no residue was left on the clothes. It is true than a front loader, where the detergent is added through a dispenser and is injected into the outer drum, is less likely to leave bits of undissolved detergent on the laundry than an overloaded top loader where the detergent is dumped on the dry laundry before starting the machine, but in either one, if the water is too cold to dissolve the detergent or too hard or too cold to properly rinse away the detergent, you are going to have problems on many counts causing poor laundering.