I can't believe hn are even discussing this.
If you can't see the difference then go right ahead and keep discussing this nonsense. Funny how the rest of the animal kingdom seems to have managed. Funny how nobody but the Japanese want these? Ever ask why the same nation that needs soiled panty dispensing vending machines also needs an electric bidet. See it for what it is, a fetish. I'm sure jonathan swift would have loved one.
Cleaning yourself with water, whether it be your hands or your butt, is not a "fetish" and I cannot comprehend why you would try to paint it as such. Why are you so scared of the idea that you'll go to the extreme of trying to dismiss it as sexual deviancy? Your argument says a lot more about you than it does about the topic at hand.
And for your information, used pantie vending machines in Japan is basically an urban myth. There may be some in fetishist sex shops, I'm not sure. I'm sure you can buy used panties in American fetish sex shops, too.