Is this just a story about this particular time and place, or is she trying to say something important about human nature?
Shirley Jackson's story "The Lottery" does not fall within the genre of historical fiction, for which it is not a tale about an event that takes place in a specific period of history.
Instead, "The Lottery" is a traditional fictional story about a grotesque practice that takes place in "a village". This practice consists on drawing names out of a box and stoning to death whoever is the person whose name is drawn.
We know from the story that this practice is as typical to the village as any other traditional event.
The lottery was conducted--as were the square dances, the teen club, the Halloween program--by Mr. Summers. who had time and energy to devote to civic activities.
We also know that it is a crazy practice, and yet, nobody questions it. Nobody even wants it gone. Like Joe Summers says "petulantly"
There's always been a lottery
Therefore, "The Lottery" is a story about what occurs when a group's sense of identity overcomes the use of reason, resulting in behaviors that are either counterproductive, or even harmful, just because traditions go on without being questioned, or analyzed.
However, it is worthy to consider that, when this story is published in 1948, news about the Holocaust and the influence of Hitler in the psyche of his country were very latent in Shirley Jackson's society. It is no wonder that there is a similar thematic line in "The Lottery" where the influence of one type of mentality can lead an entire group to engage in counterproductive behaviors.
Hence, "The Lottery" is more about human behavior than historical events in particular.