Why is it taboo to sell your own used underwear?

Why do most people instinctively say it's gross to sell your own used underwear (or items of clothing in general) but it seems to be more widely acceptable to buy used items from a stranger online? Used clothes are used clothes, why does it matter if it was from a "stranger online" vs a "stranger on the internet with a paypal account?" <br><br>I've sold all kinds of used items and kept a large majority of them unworn/unopened. I recently sold a pair of brand new-ish underwear because I bought a size that's way too large, but now I have a bunch of unworn/used ones of different sizes that I know I'll never wear because I know what size works best for me now. I've saved a few for reusable cleaning rags. My relatives have even asked me if I'd sell some to them at a cheap price since they know they'll fit the relative buying them. <br><br>It just seems strange to me that it's not socially acceptable to sell used clothing. I'd much rather buy used clothing from people with similar body types as me because I know it will fit better. I have a friend who always says "I don't know how people can buy used underwear, that's so gross!" I see their point but I almost feel like they're just being stubborn because they refuse to look at it from a logical and frugal perspective.