Edit: Thanks for removing the negative comments :)
Everyone buys thermal bottoms, and sleeping bags (naked sleepers) and a host of other things on here without thinking about it. Hats seem just as "bad" to me. Shoot, I know older fellas who melt the paint off of their bicycle tubing with the sweat on their nose, and you're buying tight-fitting baselayers from them!
Point being, soap does what it's supposed to. If used clothing scares you, that's fine, but it doesn't frighten everyone.
If you're showering regularly and you clean an already antimicrobial fabric with hot water and detergent, then I think that it's silly to think these aren't fit for use.
Someone's gonna snatch these up. Merino wool briefs are A++ for backpacking.