Because this is the callcenter mentality. If you give pax an authoritative answer, they will leave happier than if you tell them you don't know. Even if it's a wrong answer, as long as it doesn't hurt them too much.

If you didn't come to FT but took his words at face value, you would have never found out he was in fact wrong, and would have just gone and did your check in in BLL.

This is increasingly more common, and especially if you hit a callcenter in a culture where admitting you don't know is looked at more like a failure (in IT services circles, for example, Indian workers are well known for never saying no, even if they are clearly out of their depth), and well documented here on FT. And a reason why HUACA is more and more popular as a method.