A few decades ago, Darwinians and creationists had a de facto nonaggression pact: Creationists would let Darwinians reign in biology class, and otherwise Darwinians would leave creationists alone. The deal worked. I went to a public high school in a pretty religious part of the country--south-central Texas--and I don't remember anyone complaining about sophomores being taught natural selection. It just wasn't an issue.
A few years ago, such biologists as Richard Dawkins and PZ Myers started violating the nonaggression pact. [Which isn't to say the violation was wholly unprovoked; see my update below.] I don't just mean they professed atheism--many Darwinians had long done that; I mean they started proselytizing, ridiculing the faithful, and talking as if religion was an inherently pernicious thing. They not only highlighted the previously subdued tension between Darwinism and creationism but depicted Darwinism as the enemy of religion more broadly.
If the only thing this Darwinian assault did was amp up resistance to teaching evolution in public schools, the damage, though regrettable, would be limited. My fear is that the damage is broader--that fundamentalist Christians, upon being maligned by know-it-all Darwinians, are starting to see secular scientists more broadly as the enemy; Darwinians, climate scientists, and stem cell researchers start to seem like a single, menacing blur.
I'm not saying that the new, militant Darwinian atheists are the only cause of what is called (with perhaps some hyperbole) "science denialism." But I do think that if somebody wants to convince a fundamentalist Christian that climate scientists aren't to be trusted, the Christian's prior association of scientists like Dawkins with evil makes that job easier.
I reiterate that this theory is conjectural--so conjectural that "hypothesis" is a better word for it than "theory". The jury may remain out on it forever.
Meanwhile, some data to keep your eye on: Check out the extreme right of the graph above. Over the past two years, the portion of respondents who don't believe in evolution has grown by six percentage points. Where did those people come from? The graph suggests they're people who had previously believed in an evolution guided by God--a group whose size dropped by a corresponding six percentage points. It's as if people who had previously seen evolution and religion as compatible were told by the new militant Darwinians, "No, you must choose: Which is it, evolution or religion?"--and pretty much all of them chose religion.