My understanding, based on conversations with taxi drivers, is that they prefer to announce the route they will take in delivering you, to avoid misunderstanding. They might also ask you if you have a preferred route to get to your destination. It's probable that's what he was doing, and you might have misunderstood him.
On the other hand, most people in Bs As these days seem to be jumpy and that includes me. I went to a local bank the other day, and after I showed my appointment sheet, the security guard opened the door for me and asked: "why are you here?" My response? It is none of your dam business. It was not a nice response, but it irritated me that he should ask. Later, I did apologize to him because I thought I overreacted.