The question here is was what was written in that email offensive and not to be written in the workplace...

Well, this was a chatroom. I do think it's important to recognize the level of planning which goes into what someone is saying and adjust expectations accordingly.

Now that our communication tools are capturing everything we are saying in real-time, do we truly expect 30,000 people to never make a comment that could possibly offend someone else?

I do wonder if just reading a comment like this in a company chatroom (along with an immediate apology) requires taking a month off, if perhaps there isn't a reasonable accommodation that could be made here to help Danielle be successful at Apple.

How many songs do you find offensive but listen to often enough to memorize the words?

Where does it say that she memorized the words? I've never heard the song but I've heard about it and know the "hide your kids" bit. It's not like she's reciting the Gettysburg Address here.