What point is Shirley Jackson making about certain kinds of rituals and traditions in her short story "The Lottery"?

Shirley Jackson's much-anthologized short story "The
Lottery" is a particularly traumatic transaction between reader and text. Through its
narrative, the reader is relentlessly and finally compelled to ask the hitherto
taboo question: 'How much is our society also laced with mindless, but brutal
traditions?' To do this Jackson first lulls the reader into assimilating the pleasant,
even prosaic behaviour of a nameless small town. On a benign early summer day the
villagers have paused in their affairs to participate in a traditional
lottery:

The morning of June 27th was clear and sunny, with
the fresh warmth of a full-summer day; the flowers were blossoming profusely and the
grass was richly green. The people of the village began to gather in the square, between
the post office and the bank, around ten o'clock; in some towns there were so many
people that the lottery took two days and had to be started on June 26th, but in this
village, where there were only about three hundred people, the whole lottery took less
than two hours, so it could begin at ten o'clock in the morning and still be through in
time to allow the villagers to get home for noon dinner.

As
it unfolds, the narrative - as if creating a tapestry - stitches in more and more
apparently innocuous details. But at a certain point, earlier for some, later for
others, the reader begins to realize that winning the lottery is not the lucky event one
would expect. Inexorably the reader has been brought into the circle of townspeople
who pick up stones to execute the unwilling winner of the lottery, Tessie Hutchinson. At
the same time, the reader recalls that details overlooked have been preparation for the
acceptance of ritual sacrifice. This was alluded to, but dismissed in an earlier
reader/text transaction when Old Man Warner, the village's outspoken redneck
opines: "Lottery in June, corn be heavy soon." The reader, in some consternation,
realizes that he or she has become an unwilling participant and
victim of an age-old ritual of scapegoating, now moribund, where only the bloodlust
remains. Herein lies the reader's trauma which constitutes an essential part of the
meaning of the story.