In the book he notes that it started out as a derogatory term. Can't find the quote in the book but I found this

http://www.nytimes.com/2010/05/16/magazine/16FOB-OnLanguage-...

"When I asked Derman recently about his early years in finance, he said that at first he felt that quant, like rocket scientist before it, was largely a derogatory put-down for the brainy newcomers, many of them foreign-born: 'two-thirds pejorative, one-third grudging praise,' by his calculation."

And it's not a term new to HN:

https://hn.algolia.com/?query=quant%20&sort=byPopularity&pre...

Why do people play TIL on HN?