as lds people have certain quirks that shouldn't come out in a job interview? i think that is what happened. just because you went on a mission and learned stuff that, that doesn't mean that it's necessarily appropriate to talk about, nor should you do your own thing, oblivious to the thoughts of others. if you are the interviewee, understand that you are not the one in power. he didn't say that that church wasn't true. he said that the kid came off poorly.
if the kid would have at least read "interviewing for dummies", he would have fared much better.
regardless, the kid was immature.