Marginalia writer like slow-witted friend

Jennifer of Daily Gusto reflects on marginalia in novels. She’s reading a library copy of Iris Murdoch’s The Sacred and Profane Love Machine and has come across some curious inscriptions, a few of which she’s scanned in and uploaded. She explains:

As I’ve read, I’ve begun to feel I know the inscriber, who is kind of like a sweet but slow-witted friend who explains the jokes on Seinfeld. (“That’s funny because George’s mom caught him masturbating!”)