To make the point that idiocy was the name of the game.
But that’s not what the reasoning Roberts has given. The mandate “may reasonably be characterized as a tax,” although in actuality it wasn’t a tax before Roberts “characterized” it.
Look what happened with the Stolen Valor Act. The court decision striking it down was one of the most pointless decisions ever handed down -- because it was such a silly law that the U.S. Justice Department had stopped even attempting to enforce it anyway.