Laing O'Rourke Communications Assistant interview questions

Around 3 weeks from the application to a call back. Interview conducted by a newly promoted marketing manager that was either being sly, or genuinely aloof, when he said 'I am not good at interviews so lets just keep this really informal'. The Interviewer did not have much to say when asked about a new candidates potential progression for the company, proclaiming he had just been there at the right place and the right time. I got the impression that they seemed keen on me as a potential shoe-in, as I had had similar experience, but I got a general rejection email a week later. When I asked the interviewer, I was simply told I just 'didn't have the experience' - so why did I get invited to interview?