6sense User Experience Design interview questions

Someone at 6sense contacted me via LinkedIn and asked me to apply. I responded and talked to HR the very next day. But the follow up was scheduled a month away. In contrast with most interview processes, there was no initial hiring manager chat. The follow up was a full day of interviews, including portfolio review, with five people. However, after I did the portfolio presentation and answered a few basic questions, they told me they weren't interested and canceled the rest of the interviews. While I'm glad they didn't waste my time after they realized I wasn't a good fit, I'm confused why they asked me to interview at all if my fit was that bad. They had access to my CV and online portfolio for a full month before the meeting, so my presentation should not have been a surprise.