Sorry, but being insulted, especially when it's from someone I don't even know, is something I just don't tolerate. I just find it very disrespectful to jump into insults so quickly over something so small. (Or in this case, a joke.) If I get insulted, I'm not gonna let the person go off without an apology, or a fight if necessary. I'm an aggressive person in general.
That said, I don't really hold a grudge against you or anyone if it happened. It's commonplace, but it's something I generally hate. Even if I was still a mod I wouldn't infract you for a personal thing, as you haven't broken any rule. I'm not offended but it's just something that doesn't fly by me.
I'm more than willing to let it go, even moreso since you apologized and I'm not really bothered by it.