I'm not trying to point accusatory fingers anywhere, you're missing the claim. You made the claim that USA success was the direct result of slave labor. If this were true, you would expect other societies with boatloads of slave labor to be more successful. They weren't.
Since lots of places had lots of unpaid labor and did nothing particularly successful, there must be more to it. If there is more to it, it is (usually) evidence that the USA would have been successful without slave labor.
Since lots of places had lots of unpaid labor and did nothing particularly successful, there must be more to it. If there is more to it, it is (usually) evidence that the USA would have been successful without slave labor.