Ok. Biden's very closely resembles a character in MBE. Johnnie and Hunter create and sell art. Johnnie just happens to also be fencing art. Mickey Blue Eye is the art dealer [Hugh's] mob son-in-law imposter...On the other hand the ending plot of Notting Hill* revolves around a pricey (legally obtained) work of art. And the scene is one of positive class interactions and affluent sophistication.
So the joke was essentially an actor shaking their head at THE WAY reality imitates one kind of art and not another. Hope that explains it.
*I have not seen in years so my summary may be flawed in details.