Do we really need to split hairs like this? The algorithms aren't completely opaque, as they have been trained on a set of representative inputs, and are continuously monitored. They are based on neural networks, presumably, with weights inspectable by the engineers deploying the model. So it is more "nebulous" and not completely opaque.
We do, because in terms of writing english black boxes are opaque by their very nature. OP could remove "black boxes" to make the sentence correct.
You can't actually see inside a black box. That's why it's a "black box". Sure you can probe it, but that's not the same as being "nebulous", a thing you can actually see through sometimes. I expect better of HN.
