Sometimes Christians focus in on one doctrine to make it their "hallmark." I've found this to be true with many "born-again Christians." What many are saying is that unless one has the same spiritual experience as did they, they have not become "born again" as a Christian. It is similar in other denominations. Some Pentecostalists put the emphasis on "talking in tongues." They feel this is God's signature upon them that they are really "children of God." Other groups emphasize "healings" or some other "gift of the holy spirit."
However, if a Christian uses this as a litmus test for other Christians, he slips over to a dangerous area of judging others. Once done, he is not acting as a Christian...but as God.