The 13th amendment abolished slavery, if one accepts your argument we have to believe that it did not work and the institution of slavery still exists in America.
Of course constitutional amendments "work."
The 13th abolished slavery on paper.
Do you really think it abolished slavery in the minds and hearts of those who would enslave their fellow man for any reason?
Indentured servants and plantation slaves were the obvious examples of slavery in our early history, it has just changed its form today.
One point does need to be expressed in regard to black African slavery and that is the emancipation of those who survived the enslavement of their own kind leading to ultimate freedom in God’s promised land should be seen as a miraculous blessing. That blessing alone should lead to Eternal praise of the God of Abraham, Isaac, and Jacob, by the recipients and their posterity.