jeremiad
A long, dramatic speech complaining that everything is getting worse.
A jeremiad is a long, mournful complaint about how bad things have gotten, often warning that disaster will strike unless people change their ways. The word comes from the biblical prophet Jeremiah, who spent years warning that Jerusalem would be destroyed if people didn't reform their behavior.
You might encounter jeremiads in opinion pieces where writers declare that “kids today” are ruining everything, or in speeches warning that society is collapsing. A politician might deliver a jeremiad about declining values. A newspaper columnist might write a jeremiad about how modern technology is destroying human connection.
The tone of a jeremiad is pessimistic and doom-laden, quite different from ordinary criticism. If your friend complains that the cafeteria pizza was cold today, that's just griping. But if they launch into a dramatic speech about how the cafeteria has declined every single year, quality keeps dropping, and soon nobody will be able to eat there at all, that's a jeremiad.
Calling something a jeremiad suggests the complaint might be exaggerated or overly dramatic, even if it contains some truth. When someone goes on and on about how everything is terrible and getting worse, you might think, “Here comes another jeremiad.”