I was a relatively early adopter to Facebook, though not Harvard- or Ivy League-early. It didn't have a hot-or-not style rating at that time. Poking was a feature, but I'm not sure it was ever that popular.
It's a site that predates Facebook: Facemash used "photos compiled from the online facebooks of nine Houses, placing two next to each other at a time and asking users to choose the “hotter” person"
It was definitely still part of Facebook when it started rolling out beyond colleges to high school students around 2005/2006. I remember people spending way too much time rating randos in study halls back then.
Are you sure that wasn't hotornot.com or something similar? I've been on Facebook since back when it was still segmented by college (connections with people at other colleges were clunky), and I don't recall it ever having a built-in "hot or not" feature.
I think I recall what he might be talking about. I remember several third party apps within Facebook that served a similar function being popular back in the early days of Facebook. It's totally reasonable that someone might fuzzily confuse one of those for core features after a decade or so.
I agree with the initial premise, origin story more likely was nerd bros desperately wanted to get rich and get laid. Connecting the world only came around when they were told they couldn't put that into their business plan template as their mission statement.
But I have a feeling you are confusing things and timelines. Perhaps you are remembering the actual hot or not site that did just what you remember while thinking of the facemash or whatever that Zuckerberg made prior to FB that we probably all learned about when we watched The Social Network.
https://en.wikipedia.org/wiki/History_of_Facebook#FaceMash