Of course if wasn’t a stunt.
Piers Morgan wouldn’t have chosen to highlight how Meghan Markle completely dropped him as a contact - thereby suggesting to the viewer that his endless tirades against her are basically fueled by jealousy and spite. The jilted lover kind. Great look, no? I don’t think the programme is struggling for ratings and even if it were, there are less humiliating ways to get them.
Utterly humiliating yourself seems a bit OTT it gain a few thousand viewers.
The simplest explanation is usually the right one.