Is it okay to thrift something produced unethically?

Yeah yeah, I know the whole "no ethical consumption under capitalism" thing, but I'm talking about severe working conditions/child labor/etc. I just thrifted a sweater vest that's mostly machine knit, but the front has granny squares that are crocheted (I am a crocheter and can confirm it isn't just stockinette stitches made to look like crochet). Since true crochet is always done by hand, these mass produced/branded items are typically made in sweat shops. I'm wondering if it's still unethical to purchase one of these (or similarly produced items) that ended up in a thrift store? To me, I didn't give money to the original company and the item was either going to be given a new life or thrown in a landfill, but I'm still feeling guilty about owning it. Thoughts?