The Bible, in fact one of the books you referenced, says to execute whose who steal and sell others. I don't think it makes sense that the same practice is condemned and then sanctioned a chapter later. All forms of "compulsory" labor are translated the same way in many Bibles of old (The KJV translated in 1611, and the most popular, actually differentiates between servant and slave), but the Bible makes a difference between what we consider chattel slavery and servitude, what those people are alluding to. When translating people way back when, people weren't PC enough to care to distinguish, but modern translators are. Christians were forbidden from enslaving each other long before Columbus set sail. If you read the bull stating this, the language used to forbid slavery seems awfully familiar. Also, there's an entire epistle in the New testament from Paul which details him trying to get a slave free by essentially implying the slave's master would be a bad Christian if he didn't do so.
I agree that there's no way around premarital sex being a sin. Many "Christians" are comfortable doing so with a partner whom they plan to marry, but it doesn't lessen the sin. I guess it's a given Christians will sin, what one does after sinning shows if they are truly remorseful.
Anyways, you should stop arguing with people online, you came from elsewhere and just started arguing with some random guy on here.