I recommend the recent article at Slate Star Codex New Atheism: The Godlessness That Failed. (The title is meant to echo The God That Failed , a post WWII book in which six communist writers describe their disillusionment with and abandonment of that faith.) Scott Alexander is an atheist, and has been deeply involved with the online discussions between atheists/humanists and Christians/theists for over two decades. He has noticed a dropoff in the discussions, a lack of traffic and interest at the atheist sites, and a split in the group in the last few years. Bethany over at Graph Paper Diaries offers the suggestion that people became part of the New Atheist movement and online discussions from two broad categories, those who believed that religion was unscientific and unreasonable, and those who believed it was pernicious and dangerous. I believe it was likely the latter group who converted to a Social Justice liberalism and gradually just left. If liberalism is a religion, SJW's are the fundies. Alexander is usually very fair-minded. He read a good deal of C S Lewis and found him “almost convincing,” and could see how someone might embrace a Christian faith in that way.
Two caveats: Categorising subgroups is always inexact and might even be useless. I reprinted Michael Novak’s types of atheist from No One Sees God a decade ago, and it included seven versions. (The links are all shot now. So much for the eternity of the internet versus the deterioration of books, eh?) My own atheist and agnostic readers here looked over the list and didn’t find themselves described very exactly by any of the types. This should be cautionary for all of us drawing conclusions about motivations – and that includes the atheist arguers themselves, who seem to use the word “we,” more than is justified. Alexander’s discussion is specifically about the online New Atheist intense discussion types, not about the larger population of nonbelievers in general. I suspect those are very different groups, start to finish.
Secondly. I may have been drifting into using the term “Social Justice Warrior” unfairly. I have been using a definition that is convenient for criticism of them. If, for example someone actually does act in a racist or sexist way I just think of that as criminal or immoral. I don’t think of people who call that out as extremists worthy of being mocked. I reserve that for the people I feel are being ridiculous, of over-interpreting the terms and straining at gnats while swallowing camels. Rather circular on my part, and I will try and be more precise going forward. Social justice in the abstract is a very good thing. Excess is not normative, and abuse is not use.
Alexander’s discussion is already too long and doesn’t need me to expand upon it, but I did notice in the graphs on polarization that the engaged Republicans 1994 and 2014 look very similar (the 2004 Republicans had moved a bit to the middle), while the Democrats moved steadily left from 1994-2014. That isn’t any evidence for who is correct, only of who is moving, but I thought it interesting. It accords with what many observers have written over the last few years, that the left are becoming more so.