Don't forget your competition is people in third world countries who have access to effectively slave labor, but do have higher shipping costs.

Is there some reason that you are bound to do business with literal slavemasters? Are you incapable of resisting doing business with the lowest bidder?

Ask the people shopping in grocery stores. Or the grocery store owners themselves. The farmer doesn't get a say.

Is there some reason we can't refuse to import their goods or offset their lower cost of goods due to slavery by imposing tariffs?

Seriously, I can do this all day.

One reason import restrictions and tariffs won't work is that the problem is inside the (US) house: https://www.fairr.org/news-events/press-releases/meat-compan...

To address your question as why this is allowed to continue, you'd have to ask those within the US and countries that allow it to happen.

Australia addressed this in 1907 or so with the Harvester decision and other related law cases that became foundation to working conditions.

https://www.fwc.gov.au/about-us/history/waltzing-matilda-and...