Where do you think that Eliezer's body language is described as remarkably odd? If you mean "He wore glasses, had a short, dark beard, and his heavy body seemed slightly alien to him.", I'm not sure.
It might be a reference to the way Eliezer talks about his body and ideas about cryonics that only the brain matters.
The "slightly alien" thing and this:
he kept grimacing as if not quite in control of his face
Cover title: “Power and paranoia in Silicon Valley”; article title: “Come with us if you want to live: Among the apocalyptic libertarians of Silicon Valley” (mirrors: 1, 2, 3), by Sam Frank; Harper’s Magazine, January 2015, pg26-36 (~8500 words). The beginning/ending are focused on Ethereum and Vitalik Buterin, so I'll excerpt the LW/MIRI/CFAR-focused middle:
Pointer thanks to /u/Vulture.