The response to the above is simple- it is not fair or right to judge the actions of yesterday by the standards(and usually ridiculously PC standards) of today.
Paul did not forbid slavery because in his day slavery was extremely common and many were perfectly content being slaves, just as many were perfectly happy "in service” in England to wealthy families.
Now I understand the particular evils of plantation slavery in the US in the 18th and 19th century but that was 200 years ago and black persons were viewed far differently then, out of ignorance.
I certainly don’t think Washington and Jefferson were evil men for owning slaves- that’s just the way things were then and there was not a second thought about it- until the abolitionists started getting their message across.