Painting in the National Gallery (adult humour)

A couple attending an art exhibition at the National Gallery were staring at a portrait that had them completely confused.

The painting depicted three very black and totally naked men sitting on a park bench. Two of the figures had black willies, but the one in the middle had a pink willy. The curator of the gallery realized that they were having trouble interpreting the painting and offered his assessment.
He went on for nearly half an hour explaining how it depicted the sexual emasculation of African-Americans in a predominately white, patriarchal society.
"In fact," he pointed out, "some serious critics believe that the pink willy also reflects the cultural and sociological oppression experienced by gay men in contemporary society."

After the curator left, a young man approached the couple and said, "Would you like to know what the painting is really about?"
"Now why would you claim to be more of an expert than the curator of the gallery?" asked the couple.
"Because I'm the guy who painted it," he replied. "In fact, there are no African-Americans depicted at all. They're just three coal miners, and the guy in the middle went home for lunch."