"the standard of write and wrong" - ROFL!
The thing he was against was Jews as slaves. He couldn't care less about anyone else because non-Jews aka Gentiles are sub-humans. Jewish males only served 6 years as slaves then released on the 7th, Gentiles were slaves for life. So yes, he was against slavery in this regard, just as he is opposed to be a slave himself, but if he lived in that time and had the cash, he wouldn't be against owning a slave. Jesus himself was pro-slavery. Sure he said the whole, "Do unto others.." but that only applied to Jewish males because if you were a slave, "Obey your master as you would obey YHWH..." If Jesus/God thought slavery was wrong, he would have said something.
The whole thing about the Civil War... it looked like God was Pro-Slavery, then couldn't decide until Gettysburg. So how would an Perfect All-Knowing, All-Loving, God not able to "make up his mind?" Then change his mind on his stance of slavery that went againist the last 6,000 years, if the Bible were true? Remember, if anything "Perfect" changes, it's no longer perfect. The thing that ended slavery in the US wasn't God, it was thousands of people that were willing to give the ultimate sacrifice, and it meant more than Jesus' sacrifice because they knew they weren't going to come back... hence 'sacrifice.'