--Protected-- These groups in USA have some subtle, hard to prove discrimination. If you're not in the group it's hard to even perceive and/or understand (it's why the issue is so hot-button).

Like all those prospect-hires who never got a call back - as they weren't "a cultural fit for our company" on record. But maybe (and heres the nearly impossible part to prove) the hiring manager didn't like them cause they /sounded gay/ or /was a bitch/.

Edit: you downvote cause you don't think it happens or because you don't like reading about how it happens?