Am I financialy enabling child labor in 3rd world country by buying second hand fast fashion from Thrift shop and Vinted? Because I am not the one who originally bought the clothes from Shein. But buy buying it again from someone else I still use it uhhuhh this is complicated.


tldr; no, you aren’t.
My friend is a factory liaison who connects all of those factories(avoid “3rd world”, that’s a defunct, demeaning political/economic epithet) with markets around the world: Walmart, Apple, Microsoft, e’erbody, and has explained to me and shown me product orders and shipping manifests regarding the volume and production method of every company of any size in any industry; they are all operating the same way fast fashion does: overproduction and profit margin obscurity.
If you buy anything these days, from nearly any company, you’re technically financially enabling some sort of unsavory labor, but there are several things to keep in mind, primarily that your individual shopping choices do not cause and will not affect modern systems of production.
Fast fashion in particular is going to produce produce produce. It doesn’t matter how much people buy, they will keep producing absurd amounts of clothing because the markets don’t know how truly cheap clothing is to produce; the profit margin is and has been worth massive overproduction for years. The majority of fast fashion products can instantly be thrown away and become mountains of trash and those factories will still be turning an enormous profit.
If you are buying secondhand, you are participating less in that system of production, and that’s really all you can do and it is a laudable choice! Nobody except greed was really responsible for overproduction in the first place.
You literally wouldn’t believe the capacity, production, and near zero cost these factories produce all items in.
Fast fashion is not unique. If you buy an air fryer, or a smartphone, or dishes, blankets, nearly anything from a factory, it’s the same system and method of production.
You probably don’t have the option to buy handmade dishes, blankets, and you definitely don’t have the option to buy handcrafted electronics, and that is not your fault, that is the system that mercantilism leading into industrial capitalism facilitated.
Buying secondhand is the best you can do to not participate in an unhealthy economic system, and that’s a great choice. Factories, however, are operating on such wide margins that they will produce regardless.
And this is why we all go to the bad place.
No matter how complex or inefficient the orphan grinding machine, if you buy something second-hand and the person you bought it from buys a replacement with your proceeds, you are contributing to that sale and thereby funding the orphan grinding machine.
Your secondhand purchase incurs no responsibility for someone else purchasing a new product.
Secondhand is a very good way to not participate in the system of overproduction.