It was also a part of the economic system of the antebellum American South. That's not a defense.
Were they forced to own slaves?
He never taught that slavery was immoral.
Apparently, there is no Philemon 10:17, and Philippians 2:3 says, "Do nothing out of selfish ambition or vain conceit. Rather, in humility value others above yourselves" Not much about treating slaves as brothers there.
Non sequitur. Besides, you can't know what Jesus' followers did.
The Golden Rule is mostly ignored. Most slave owners in the American South were Christians. The Golden Rule didn't help them much.
Nor was it much use to loving same sex couples that wanted to marry or even to get a wedding cake. The church fights homosexuals tooth and nail and defends the right of Christians to discriminate against them.
In America, Christians are presently trying to impose Christianity and its values on non-Christians by piercing the church-state wall and diverting public funds to the teaching of creationism, for example. Not very neighborly.
Evangelical Christians voted overwhelmingly for Trump, who promised to take away the health insurance of the working poor (Obamacare).
And then there's this from
Trump supporter thought president would only deport ‘bad hombres.’ Instead, her husband is being deported. :
"a successful businessman, respected member of his Indiana town and father of three American-born children - languishes in a detention facility with hardened criminals as he awaits his deportation back to Mexico, the country he left in 1998 when he entered the United States illegally ... Supporters say the 43-year-old has never broken the law and doesn’t have so much as a parking ticket on his record. The mayor of South Bend, Ind., the conservative community that the Beristains call home, called him “one of its model residents."
That's how evangelical Christians voted. Where's the Golden Rule there?
The way that you and many other Christian apologists see and depict Christians and Christianity is not the way either appear from the outside looking in.
Humanists, who seem to have a much better developed moral compass, embody the Golden Rule much more faithfully than Christians. For example, humanists don't want to force their religious views on anybody. They support secular government and freedom of and from religion. That's what the Golden Rule would have one do.
There is nothing anywhere in the Bible condemning slavery, and much to promote it.
America had slavery until the mid-19th century. And Christians fought Christians who defended the practice with their Bibles to abolish it