You shouldn't have apologised. Shame on you for giving in to the righteous hordes, from a moral standpoint. From a business standpoint, it may have seemed the only practical action, but in my mind you compromised your personal integrity by apologising to these people, and I'm sorry that you did.

I believe in the end it was something that deserved an apology, but doing so certainly did compromise my personal integrity. I guess compromising it one time won't kill me.

I don't see any problems with dark humor, much worse is said around my office. No one could possibly be serious when saying that sort of stuff.