Pete,
As far as I can tell, there is a class of people who thinks that either cleaning lint is inconvenient, or that it is sometimes gross.
I used to have a housemate back in early 90's that not only would pick up the FilterFlo's pan with the tip of his fingers, he would shake and bang the thing against the trash can until the ball of lint would fall off. It was worse with the dryer's lint filter, because the screen would tend to grab and hold the lint.
We used to poke fun at him, that the lint was washed, rinsed and dried or, worse, that the lint was clearly just as clean (or dirty) as his clothes. He would just make a noise like he was grossed out and not touch it.
One way or another, I have the impression that people write so much to consumer's magazines complaining about anything that doesn't have self-cleaning filters that the magazines downgrade stuff with manual clean filters.
I believe that is one of the reasons we've been witnessing the disappearance of lint filters in washers. ;-)
Cheers,
-- Paulo.