I don't think you can call that an ad hominem attack. For one, he's not talking about the actual author of the quote (the writer), and for two... well, it's just not an attack at all.
I find it very relevant that a person who does all these things is a (fictional) character that lives for thousands of years; that means he has plenty of time to learn a lot about many different fields and trades. Normal humans don't have this luxury.