it's not hoovering,, he's taking you hostage... He's testing you to see how much crap he can say to you before you scream "Shut up"...
You can always just turn away and get busy doing other things, it's not rude, you didn't ask to join his fan club,,, or start exchanging the child in public where the ex can't take up your time the same way...
He knows,(narcs always know) that the shallow blah blah blah is a trigger for people trying to get away from them...
He's had practice and he's really good at pretending that he;s being friendly when instead, he's holding you hostage with the "commercial" of himself..