Oh, I think there's a lot of ignorance and real hatred out there
Some people simply don't feel good about themselves unless they can put other people down, and devalue them. Lacking intelligence and/or sophistication, they adhere to beliefs of group identities and stereotypes, whether based on race, gender, ethnicity, whatever. And backwards religious beliefs do play a major, major role in the widely practiced discrimination against gays.
I think economics comes more into play when jobs and compensation are involved, in the workplace.