How can it not matter. Once a person that wrote from the heart about matter concerning maybe a few, maybe very few, once fallen victim to his own greatness that person will seek out subjects that appeal to the masses no matter the depth of his own insight.
He's not saying Guy is wrong. He's saying you're gonna have to come up with a more cogent argument than "He was right back then, and he's still right today". Basically, the burden of proof is on you since you made the original claim.