After reading this and a few other of @stellabelle's posts, I was gonna (sic) commend her for coining the brilliant and expressive neologism, "shitpost." As a language teacher, language student, writer, and editor, I can only approve.
The term "shitpost" describes quite well those posts that she is referring to. Most other words or phrases would not describe them as accurately or succinctly. (Only 8 letters! 4 of which are necessary)
Furthermore, while some might take offence, the term "shit" is hardly an offensive word. When we use it in such phrases as "bullshit" or "when the shit hits the fan" or "SHTF" or "Holy Shit!" few would care. Same with "WTF,' which is now completely acceptable, while to spell it out in full may not be acceptable.
I expect we might even see "shitpost" in a future edition of the Oxford dictionary. If it's not in the next one, I'll notify Oxford myself, and advise them to include it in the subsequent edition.