“These are federal laws already. Why the heck do they need
city laws?”
Which federal laws prohibit discrimination against gays in housing and employment? I’m not aware of any...
Perhaps I was a little to definitive in my response. Real estate law may vary by state, but real estate agents are forbidden from discriminating against gays in rental or property transactions under various laws. Could an individual renting or selling their home or property discriminate, perhaps in some states.
As to employment discrimination against gays, it appears this is handled at the state and local level, while federal government hiring has interpreted (or extrapolated)
that they can't discriminate against gays under the existing discrimination laws.