A POB issue, but the following extract from the New York Times offers some good points:
Folks is a homogeneous social group as contrasted with the individual or with a selected class,” according to Webster. It originated from the Old English “folc,” or “people,” and expanded in the 19th century to incorporate the concept of “folklore,” which included a sense of passing along a common narrative.
Early usage of "folks" in politics:
“Folks” made occasional political appearances in the early 20th century, often in the form of “just folks” — “just” underscoring the attempt at humility. In a Times account of President Warren G. Harding’s 1923 trip to Denver, he was commended for his accessible manner. “He was ‘just folks’ and people liked his ways,” The Times concluded. A clip from 1932 described F.D.R.’s campaigning in New York for the future governor Herbert Lehman. “All was neighborly, homely, informal; from dairy farmer to governor, from garden trickster to lieutenant governor,” The Times reported. “Everybody was just folks.”
More recent usages and current connotation of "folks":
In recent decades, “folks” has become more of a politician’s crutch. As Favreau noted, it solves the problem of how best to refer to any collection, assembly or generic mass.
Alternatives abound but can be problematic:
“The American people” was an old standby, as in “the American people are sick and tired of so-and-so.” But this can seem a little presumptuous, especially as the population has grown more diverse, globalized and splintered. “The People” (as in “power to the people” or “we the people”) enjoyed an uprising in the ’60s and ’70s. Backlash ensued: “Unfortunately, I Do Not Identify With the People,” said a headline over a 1972 Times column by Kathryn R. Bloom. “The People is the little guy. The People is honest. Decent. Sincere. Simple, even. The People is fed up.”
The People — evidenced by its capitalization — was at least meant to be a term of collective empowerment. The People is an awesome, singular force; as opposed to “the little guy,” which was Harry Truman’s favorite, or the “common man,” preferred by F.D.R. Today, neither would suit the inflated self-involvement of baby-boomers, let alone millennials.