Are you American by chance? I find that lots of Americans seem to want and even feel they're owed that kind of false sincerity/kindness from "low skill" workers they interact with.
Also I doubt it got to the point of someone telling OP to fuck off just for asking if there's an elevator, there has to be more to that story.
Also also there's no indication that the same business that owns the bar is the same business that owns the building, maybe they just rent a space on the bottom floor. So again, not the bartenders responsibility to apologize for something they have no control over, and possibly they're not even a representative of the same business that owns the building that chose not to include the accommodations.
In regards to accessibility accommodations, the only responsibility I can see to the bartender is telling people that there's not an elevator when they ask and he seems to have fulfilled that.