Yeah, ok, apparently I lied. I see the thread has moved on to the "girls" issue, and I wanted to clarify: my comment focused on the longstanding and highly-insulting use of "boy" and "girl" to refer to black people. I assumed that this was one of those "bygone era" things that no longer existed except maybe in certain affirmatively-racist areas. So to hear it as just a casual, automatic usage in a public restroom in my area was shocking.
Really: if you see an older white lady -- a grandma type -- manning the restroom, who is going to refer to her as the "girl"? Wouldn't you show her the respect due her age by calling her a "lady" -- "don't forget to leave a tip for the lady"? Or a title, like "cleaner" or "attendant"? I have trouble conceiving of anyone calling a white grandma a "girl." And yet without thinking, change the color of her skin, and that's the first thing that trips off the tongue?
When we talk about microaggressions, that's the kind of thing we mean. Obviously, there is nothing wrong with the word "girl," and the lady who said it was not using it as an epithet in any intentionally negative way. And yet imagine being called "girl" or "boy" repeatedly, when your white counterparts are called "ladies" or "gentlemen" or "women" or "men" other more respectful things. And then imagine knowing that the people who call you "girl" aren't actually trying to be mean -- that's actually worse, because it means they inherently, unthinkingly see you as meriting less respect than someone who is exactly like you but white.