Human beings have a remarkable and irritating tendency to latch on to specific issues for dear life, while sweeping other issues under the rug. The level of concern people have for specific issues almost never correlates in any way at all with the actual importance of those issues. Perception is everything, and reality falls by the wayside.
The issue of "toxic" air inside aircraft is one example. Another, which I've encountered more and more recently, is the issue of "chemtrails," that is, the belief that condensation trails contain vile toxic substances in significant quantities, beyond water and carbon dioxide.
Still another example is the disparity in coverage of two recent accidents. After the first accident, the pilot in command was promptly canonized; after the second, much more recent accident, the crew is being posthumously vilified. And these attitudes have virtually nothing at all to do with the actual circumstances of each accident and the probable causes. It's all illusion.
It seems that all you have to do is put an idea into a person's head, and he or she will run with it, improvising and imagining all the other details along the way. Most people will in fact prefer the imaginary details to the real facts, even if you offer to give them the real facts, and the fewer facts that are available, the more intense and detailed the imaginings.