FRiend, I see perfectly well what your problem here is, and I think I can help clear it up.
Your problem is the definition of the word "slave".
The Bible absolutely did not mean the same thing in referring to Hebrew "slaves" as American secessionists meant referring to their "peculiar institution".
For starters, ancient Israelites could not lawfully become slaves except for specific reasons, usually to pay off a debt.
And even then, slaves had to be given their freedom after seven years.
So by our understanding of terms, that's not really slavery, rather it's a long-term employment contract with "wages" used to pay off debts.
Once the contract is fulfilled, the "slave" goes free.
In colonial times, these people were referred to as indentured servants, and indeed, in the very beginnings, that's also how African slaves were treated.
Only over time did slavery as it was known in 1860 develop, where only people of African descent could be slaves, where slaves were considered sub-human (see Dred Scott) "property", and even when gaining freedom were still subject to vagaries of laws which might re-enslave them (as was declared by the Confederate government during the war).
Note Deuteronomy 23:15 ESV:
So how is it that those who claim slavery was "no sin" cannot see that the Bible condemns both the capturing of slaves and returning escaped slaves to their masters?
If slave-holders were truly interested in Biblical views, wouldn't such verses give them pause?
Keep for future reference - WELL ARGUED!
It is generally believed by Biblical scholars that the sabbath and Jubilee year provisions of the law were aspirations never actually put into practice. It is possible (male) slaves were indeed freed after seven years, but women slaves and their offspring were for life.
And non-Hebrew slaves were treated as permanent chattel, just like all the nations around them did.
It is true the first few years in America blacks were apparently treated as indentured servants, just like whites were. Based on Caribbean and Spanish precedent, this changed pretty quickly, with the adopting of civil (Roman) law precedence for dealing with slaves over English common law, which had no provision for chattel slavery.
Excellent analysis and commentary. Biblical ignorance used to prove a point is almost a specialty at FR.