I suspect it took so long because the answer is, "Yes, but no." Someone might say, "There's no sign for TOOLBOX in ASL! How can it be a useful language?!" The answer to that is "Yes, but no*," too.
Here's an excerpt from an article from here:
NVC shows us a big difference between mourning and apology. Apology is basically part of our violent language. It implies wrongness - that you should be blamed, that you should be penitent, that you’re a terrible person for what you did. And when you agree that you are a horrible person and when you have become sufficiently penitent, you can be forgiven. Sorry is part of that game, you see. If you hate yourself enough, you can be forgiven.
Now, in contrast, what is really healing for people is not that game where we agree that we’re terrible, but rather going inside yourself and seeing what need of yours was not met by the behavior. And when you are in touch with that, you feel a different kind of suffering. You feel a natural suffering, a kind of suffering that leads to learning and healing, not to hatred of oneself, not to guilt.
From where I'm standing, this NVC mourning is an apology that connects people, rather than sends them to the doghouse. My partner can really tell why I regret so much stepping on his foot, and he really knows what value fueled that regret. I don't get stuck in that place where I cry all the way to work because I got stuck in an "I'm sorry" spiral of lamentation from which I can't escape.
Other people have done the work of writing examples for me, and better than I could. This example is from here, wherein the author is not afraid to use the word "apology" to describe this NVC communication**:
*Sure, there's no single sign for that thing, but Deaf mechanics across the nation have no trouble telling their co workers, "The 5/8" ratchet head is in the third drawer down from the top in the red toolbox by the arc welder." In fact, they have less trouble than their English using co-workers. Heck, the Deaf mechanic will also tell me exactly where in the toolbox drawer it is, and it will take much less time. But I digress.
**It fills the same societal function as an apology, so i'm cool with calling it the same thing. Like when I put salsa and spicy vegetables in a leaf of romaine lettuce; some object to me calling that a taco, but it's in the ballpark of tacoville.