Amusingly enough, I too discovered the "you have to believe in Jesus" clause in college and for a similar reason (I like to joke that I was clearly absent from Sunday school that day but in retrospect it boggles my mind that I somehow missed this major tenant of Christianity). A very religious friend of mine turned to myself and another of our friends and told us point blank that while she considered us good people, we were going to hell. As she was completely serious about the entire thing, it was rather off-putting.