American Express Data Scientist interview questions

I got the email about the position through the university emails. I sent my resume to them and surprisingly after just 1 hour they sent me some timeslots to interview with them! They also provided me a conference call number along with a passcode to call them. In the day of interview, there were basically three people, one of them was a leader and the others were data scientists at AMEX. They started with explaining their background and wanted me to talk about mine too. After that, they asked two technical and basic machine learning questions. Questions were average and I solved the first one correctly and the second one almost correctly. It seemed that they had already chosen their candidate at that time and I've heard this from one of my friends who had applied for the position before me and got the onsite interview while I hadn't had my interview yet! I don't know why they still interviewed me while they already knew their right candidate?? I would say this is absolutely not fair while I had a pile of related publications in my resume compared to my friend who didn't have any paper at all!