We should give organization more credit for being a sustainable behavior.
This even happens at the level of our own houses. I feel very bad whenever I have a nagging feeling that I own something, but can't find it, and now I need it, so I might have to buy a new one. Materialism is something I fight against all the time. I do not want to create the need for more stuff made in factories. If a can of beans gets lost it can expire before you get to eating it. If a book gets left on the basement floor it gets moldy and no one wants to read it.
Kids toys are the worst. A puzzle is fun, and cheap, but if you don't take care of it and a few pieces get lost it's now worthless and you might as well throw it away. For it to keep its value, you have to put all the pieces back in the box.
So it is with the rest of the world. If I buy a pair of womens jeans size 10 tall I don't want to have to send them to a thrift store, what are the odds they'll go to another person as tall as me? They'll be bought up my somebody, sure. Then they'll shorten them. Then the tall person a few states away has to buy a brand new pair. So I do the work of ebay or try to find some site that adds data to the junk, doesn't just throw it on a shelf.
"Donate" is too nice sounding a word for bagging up the things we don't want and sending them to a thrift store. I do it, but I don't feel good about it. There are so many of these stores and they're stuffed with the things Americans don't want. They're not all good. The Salvation Army is anti-gay There was that news two years ago about Goodwill paying its disabled workers less than minimum wage because "it's legal", when their own CEO made $750,000 a year.
I've been trying to go into the thrift stores I donate to and make sure they're trying. I favor the ones that sort the baby clothes by sizes and keep the matching shirts and pants together for kids outfits, that put a little effort, maybe charge a little more but that's okay.
Being green means finding ways to not buy stuff, and prevent everyone else from buying stuff, as much as you can.