Rod Serling had already written episodes that touched on assassinations of American Presidents. 'Back There' was about the night of Abraham Lincoln's murder. 'No Time Like The Past' included a meditation on whether or not to interfere with history by trying to prevent the assassination of James Garfield. Finally came the subject matter Serling did not expect to have - his response to the murder of John F Kennedy.
Without doubt this episode is preachy. At least Serling made sure 'The Twilight Zone' put it's head above the parapet on the subject of civil rights. At it's best the series was superb at revealing the dark side of human nature, though usually in a universal and timeless way. In this case the message concerns the present time and specific places. Michael Constantine holds the production together well as Sheriff Koch, while Terry Becker revels in the role of the condemned man, Jagger. Not a very good drama on the whole, the tone is of uncompromising disgust of racial hatred.
I think Rod Serling was right to pause great story telling and imaginative scenarios and urge reflection on such a great issue at such an important time.