Yeah, I can see caring about a white dishwasher if having your kitchen match is more important to you than being able to wash dishes in the machine, and if nobody has that color you'd rather wait until you can buy a new one yourself. Personally, I'd take a purple dishwasher with green racing stripes over not having one at all. And I'd care more about features than color! (Our current one has no sort of delay feature, so you can't set it to start in an hour, you can only set it to start immediately.)
I guess, to me, I wouldn't so much have a problem with a person posting, say, "WANTED: baby stuff" and then saying, "Hey, I'm having a baby soon, and if anybody has anything they're ready to pass on, please let me know. I'm particularly interested in a crib, swing, bouncer, and boy baby clothes." I mean, what's the harm in asking? They grow out of it so fast, and sometimes people keep it for years in case they have more kids, then they decide not to, but it might still take them a while to get time to go through it.
What I would have a problem with would be, "WANTED: baby stuff" and then saying, "I'm having a baby and need tons of stuff! I'm interested in a white Storkcraft crib, Eddie bauer bouncer, swing, and high chair in sage/brown, Eddie Bauer musical rocking bassinet, Gap or Old Navy baby clothes for boys, preferably new." Riiiiiight.