I'm not sure what a poetry example would be, but in my opinion the key theme of "The Lottery" has nothing to do with the stoning, per se. The theme is that people can blindly adhere to stupid/evil customs and beliefs just because things have "always been done that way." The stoning is secondary to the fact that the people of the village routinely follow a custom that they know is going to result in a death to one of them.
You might get a couple of different answers to this question because after the infusion of Islam in the American culture there have been at least 5 new poems published dealing with stoning from both amateur and published poets.
As far as classical poetry I can think of Alfred, Lord Tennyson's "The death of Œnone" and Tomas Boyd's "The Stoning of Darragh" are two that jump to mind when dealing with barbaric rituals, expectators, and unneccesary punishment. You can also check out poetry forums such as the one in the link provided for other input from readers regarding shocking poetry and prose.
"The Stoning of Darragh" is my choice of a poem with a similar theme as "The Lottery."