Probably because I was raised evangelical and kept at it into adulthood, and all my family and closest friends are Christians, too. Specifically thinking about climate change, Christians really only have 3 responses that don't involve outright denial or depending on us to "innovate" our way out of the problem (neither of which are real responses):
1.) Recognize climate change is real and it's us Americans that bear a lot of that responsibility. Then, act accordingly by supporting efforts like the GND to mitigate the problem as much as possible. Also, will probably need to do a little bit of #2, too.
2.) Recognize climate change is real, just say we either can't or won't do anything about it, so they commit to a program of accepting refugees (and it's gonna be a lot of refugees) from parts of the world that impacted by climate change. Throw the door open.
3.) Recognize climate change is real and it's going to displace tens and probably hundreds of millions of poor and desperate people all over the world, while the US will, at least for a while, be ok. And instead of doing something to stop it or accepting climate refugees, just say fuck it, let them die. Let millions and millions die because we love our Escalades and can't give them up for electric cars because that would be gommunism. Oh and if you try and get in here we'll just shoot you dead.
So of course, outside of a few Catholics and liberal protestants, the overwhelming majority of Americans Christians are gonna go with option #3. Despite being the "salt of the earth", having this belief that their religion is correct and calls for them to be compassionate, and that God cares about every single human soul on earth.
I get that the hypocrisy isn't really surprising to most folks here, but for me it's very personal. I remember some friends and family crying when they found out I deconverted. A couple tried to get me come back. They couldn't understand, they couldn't see the holes that I see. In their heart of hearts, they believe their religion is good and beautiful. They think it truly reflects the nature of God. And I know they care a lot about "winning souls". And yet, these same people can't see how absolutely ugly and awful the results of their beliefs are. It just pisses me off, is all.
And that's the thing, they think that they can just let millions die because being "Christlike" in their personal lives is all that matters... then they act all shocked and hurt that anyone would leave the religion and think it's bullshit in part because of that.
I've never understood the "personal" aspect of American protestantism. Like stfu dude Jesus is some Jewish dude who died two thousand years ago he doesn't care about your highschool football game or whatever inane shit you're bothering him about.
Americans are selfish and conceited. Not to mention for the overwhelming majority of evangelicals, Christianity is just their cargo cult to help them get through life. "Jesus" just replaced the little household idol you might pray to for a better harvest or whatever. Also the focus on the personal necessarily avoids addressing communal and structural issues.
A hyperindividualist, atomized culture produces hyperindividualist, atomized religion.