In middle school I learned about imports and exports and, as a suburban kid, I realized that I didn't know anyone who made physical products, and wondered, how can we have nice things without making things in return? Then i found out it was all exploitation and it always has been
This is probably the most simple, undeniable axiomatic truths around the sustainability of capitalism. You just can't grow forever on a bounded planet, and yet capitalism needs to always grow.
I find that you can get even the libbiest of libs to accept this contradiction. What they do with it is up to them of course, but it's one of those truths that is very powerful, because of how simple it is.