I wonder whether there would be also other options, but one very important aspect is the smog: the city center is where many industry-relevant things meet: the factories are all around it, transport, cars... and since it is surrounded by bad air, the air takes longer to dissipate. This is especially visible if the city is in a valley, such as Mexico city foe example.
One of the major reasons why Americans distrusted public institutions like the government was because of the publishing of the Pentagon Papers. This series of government documents that were supposed to be classified, essentially showed that the US federal government had been lying about the progress the US was making in the Vietnam War. These documents caused outrage all over the country, as thousands of American men were drafted into this military conflict for what seemed like a failed mission.
