Given the number of thrift store “rag bags” I bought to use as rags and how most are still in good condition or better – some even unworn – I’d sooner save a step and just keep them as rags myself. Or cut them into a tank. Or upcycle them into totes.
On more than one occasion, I have purchased the culled shirts from other Wooters.
There’s also the aspect that my shirts from shirt.woot, Threadless, and other crowdsourced sites are designed by folks we interact with here on the forums. Sure, I may have bought it from (insert shirt site here), but the reality is that I’m buying (insert artist here)'s shirt.