> Is this a reference to Magnus Pym, the main character in A Perfect Spy by John le Carré?

No, probably a reference to https://groups.google.com/g/eunet.politics/search?q=magnus%2...

I wasted too much time (not that much, but any time on this topic with a "true believer" like Magnus was completely wasted) arguing objectivism with him as an undergrad...