Maybe they wanted to be shielded from the noise and wanted to concentrate. We may never know. It is true they are easily led, that I agree with but unfortunately the path they are going down is one with no rational end for them or for the society if they were to be successful.
The a hole in El Paso was like a Ted Kazcynski wannabe, he used a gun rather than a bomb because he did not have the mental power to carry out that type vendetta against society.
In Texas one needs to be concerned with getting shot in that situation. So situational awareness should have over ruled noise cancellation.