Sometimes Customs does random shit like that.
I went in to Canada one time and they asked me what I did for a living, how long I was going to be in the country, was I going to do any work there. I mean, wtf? I was just visiting a friend.
Another time in 2018 I came back from Ukraine and flew into JFK. The Customs officer asked me what I was doing there, who I saw there, blah, blah, blah. I told him I visited there because my mother's family lived there before moving to the US. Makes me wonder if they knew some shit was going down ahead of the war and they had to be ever vigilant about what Americans were doing over there.