I don't really see it as a question of "separating art from the artist". That's usually invoked when other aspects of the personal life of the artist has the potential to distract from the art itself.

The parent comment is closer to saying that Picasso wouldn't have been Picasso if in an alternate universe he had avoided controversial/politically charged subjects like the Spanish Civil War and instead appealed to the lowest common denominator for a mainstream commercial audience to sell postcards.