I think that some allopathic medical schools/centers have very "old school" approaches to HR and management decisions. I was looking around the NYP-Columbia website and found zero DOs on the staff. I am aware, from reading lots about Columbia's MD admission for my wife that they tend to be traditional (read: narrow-minded) in other ways, too.
I am willing to bet that there are some old, wrinkly MDs out there in high administrative positions at some institutions who believe that DOs are quacks.
But old MDs don't last forever...
A hospital HR department will typically have no say in what physicians are hired. Usually it is the department itself that will conduct the search. If you have a bunch of old-school surgeons in a department, chances are they will still think negatively towards DO.
As for UCSF (omitting Fresno except for one)
Medicine
Alyse Gabriel, D.O. - Clinical Instructor
Robbin Green-Yeh, D.O. - Assistant Clinical Professor
Massoud Mahmoudi, D.O.,Ph.D. - Assistant Clinical Professor
Larisa Nadukhovskaya, D.O. - Clinical Instructor
Silver Sisneros, D.O. - Assistant Clinical Professor
Michael Adam Tom, D.O. - Assistant Clinical Professor
Dermatology
Nicholas Diakon, D.O. - Assistant Clinical Professor
Sharon Gerardi, D.O. - Assistant Clinical Professor of Pediatric Dermatology (Fresno)
Family and Community Medicine
Gary Gray, D.O. - Assistant Clinical Professor
Steven Levenberg, D.O. - Assistant Clinical Professor
Jeannie Pflum, D.O. - Assistant Clinical Professor
Veronica Vuksich, D.O. - Assistant Clinical Professor
Pediatrics
Donald Fields, D.O. - Clinical Instructor
James Hopkins, D.O. - Assistant Clinical Professor
Psychiatry
Richard Land, D.O. - Assistant Clinical Professor
Laurie Richer, D.O. - Associate Clinical Professor
Doris Tan, D.O. - Assistant Clinical Professor