There was a TV show quite a while ago that showed the unpacking of some imports from other countries. I think this one was from India. Guess what the goods were wrapped and packed in? Clothes from the US. Seems that a lot of the thrift stores simply have more than they can handle and they end up selling a lot by the pound and shipping to other countries. It's cheaper for them to wrap and cushion their exports in old clothes from the US than it is to pack in paper or other wrapping.
Anyway, I've never felt like thrift stores were only for the poor. Anyone who buys things there is providing $$$ to the organization.