Jeremiad
Etymology
From the prophet Jeremiah of the Hebrew Bible, associated with the Book of Lamentations, which grieves the destruction of Jerusalem in sorrowful, denunciatory verse. The French "jérémiade" and then English "jeremiad" came to name any prolonged tale of woe, especially one warning of decline. It implies both grief and reproach, not mere complaint.
noun · /jer-uh-MY-uhd/
A long, mournful lament or bitter denunciation of the times.
What it names
The exact word for an extended prophecy-of-doom complaint about moral or social decline.
Example
His op-ed was a jeremiad against the decline of the public library.
Related idea
A jeremiad mournfully denounces the decline of the times; a diatribe is simply a bitter, sustained verbal attack — lament for a fallen order versus plain invective.