Facebook's NY office is also significantly, disproportionally smaller than Google's. Google's NY office is the largest outside of California and is in many ways a second heart of the company, it really doesn't feel like a remote office. Facebook's NY office is extremely small even considering that Facebook is a smaller company than Google (their largest office outside of California is, IIRC, Seattle).
In theory we have just as good a recruiting presence on the west coast, and we have an office out there to be based out of as well (I am all for completely remote, but have yet to get upper mgmt comfortable). In practice, I doubt this is true, and also working for a hedge fund probably has a lot less draw and prestige associated with it out west.
This may account for it but I still find the discrepancy to be unusual.