I guess it's a personal preference. Most of my CDs are off swap sites but the majority I've bought new. Even those I've bought used are in excellent condition and, like you said, CDers are sticklers about their washing routines.
There is a difference to me in a newborn prefold that has only been used a couple weeks (and everything comes out in a good hot wash) vs. a one-size diaper that could be used for 1yr+.