Are Christians Wrong to Believe in Only One Way?

Paul Copan comments on how those who quickly criticize Christians for believing they hold to the one true faith are wrong in their own assumptions. In his book True for You, But Not for Me: Overcoming Objections to Christian Faith he writes:

For the relativist, it's a curious assumption that those holding to the reality of absolute truth are absolutely arrogant. There's no intrinsic contradiction between (A) holding firmly to convictions and (B) treating with love and dignity those who disagree; living harmoniously with people who hold radically different views is a hallmark of maturity. We'd all benefit from the courageous words of qualified people who display both firmness of conviction and civility (or respect)-as Paul says it, "speaking the truth in love" (Ephesians 4:15). Martin Marty (b. 1928), noted observer of religion, states that the problem of modernity is that the people "who are good at being civil often lack strong convictions, and the people who have strong convictions often lack civility."