Sorry - I don't buy this line. I have never been a Dylan fan - but many conservatives don't like him because they think he was some kind of "anti-war" icon in the '60s.
If you check the facts, Bob Dylan was NEVER against the war in Vietnam.
The media and the left-wing music industry tried to paint him as anti-war, but if you read his comments he always supported the troops and their mission.
John Williams, who wrote the music for Star Wars, Indiana Jones, Superman, Harry Potter, Jaws, Close Encounters, E.T., Schindler's List, Jurassic Park, Midway, Paper Chase, Poseidon Adventure, Towering Inferno, Diamond Head and many, many movies from the 60s and 70s (watch for his name on the credits of many films from back then - his earlier movies he is listed as "Johhny Williams") - I would not consider his talent as "insignificant".
Nobody in their right mind would describe Dylan or Williams this way.
The writer was joking - being sarcastic. He likes Dylan and Williams.
It was sarcasm