The religious progressives were the predecessors of today's progressives, so today's progressives can take credit for abolitionism, though they are embarrassed to do so, since they do not wish to recall their Christian past. They were already ditching the New Testament for its horribly reactionary position on slavery and marriage, and while they purported to say "Jesus is Lord", they were already demoting him from God to chief community organizer. As Mencius argues, as recently as the 1940s, the predecessors of today's progressives identified themselves as explicitly Christian, though when they finally threw Jesus under the bus and allowed the Jews in to join them, it was in fact less of a change than one might expect.
Mencius argues that they finally openly ditched Jesus so that they could impose their religion in the schools without running afoul of the first amendment, though perhaps letting the Jews into an explicitly progressive establishment also had something to do with it.
Why is this so heavily downvoted without a counterargument?
The notion that modern American progressivism is sociologically or memetically speaking the descendant of various Christian religious groups seems plausible and several points speak in its favour (including the heavily upvoted father of this comment).
I find this voting pattern especially strange considering that Mencius Moldbug is read by quite a few people on Lesswrong so the theory shouldn't be that shocking in itself and people are generally quite detached and reasonable when discussing even controversial issues here (with the exception of gender relations).
I wanted to bring attention to two posts from Razib Khan's Discover magazine gene expression blog (some of you may have been readers of the still active original gnxp) on the polemic surrounding Pinker's The Better Angels of Our Nature.
Relative Angels and absolute Demons (and the related But peace does reign! )
I generally agree with some of his arguments, but found this quote especially as summing up some of my own sentiments: