How is this the case? Presumably the scenario where they have live camera feeds and a security guard recognizes a banned person on them and removes them would be fine. Why does replacing the human with an algorithm legally make a difference? Did people consent to being facially recognized by a human security guard?

I think that it's analogous to when my genitals are fondled by a TSA agent because I opt out of body scans. The memory of the feeling of them caressing my shape lives on only in their brain instead of being permanently recorded in a database.