I think it is a topic of interest at FR because Halfwit and MeGain have become exemplars of exactly the type of preachy, hypocritical, lying, limousine liberal we all want to see publicly fail and be drop-kicked into permanent obscurity. Prince Charles annoys us in the same way at times.
True. Another reason, I think, is lots of people have a family member or friend who married a Meghan type, and seen that family member or friend seem to change for the worse like Harry (although Harry was probably always a self-centered spoiled jerk, but it was not so obvious before). They have also witnessed all the drama, alienating, etc. that goes along with having a Meghan type marry into their family or circle of friends.
I think you are right. The problem is the “bread and circuses” crowd won’t let them fail so we never get the satisfaction of their karma comeuppance.