I can't really speak towards the whole "N" word thing, as I'm not black, but had the same circumstances occurred and she'd said "Faggot" instead, would I be offended? Sure... a little. Would I hold it against her in the same way she's being treated now?
No... I really don't think so.
There was a time in my life when I could have been devastated by things people said to me, or about me, but ultimately I've since learned that whole "sticks and stones..." thing, I consider the source, and attempt to be the bigger man and not hold peoples' ignorance against them (too much).
Do I think she's legitimately sorry? Yes.
Do I think she's trying to cover her ass and save her business? YES.
Do I think she should be raked through the coals THIS much over it? No.
I think she learned her lesson, and I think there's a lot worse grievances going on in the world in general, and worse things that other celebrities are doing than what her circumstances are.