Because what Jesus did is as important as the theology, at least if one is a Catholic.  Read the Apostles Creed and tell me how that should be re-written if Jesus' acts are irrelevant or so incomprehensible as to be interpreted only by theologians.

A big part of the Gospel message is that there is a kingdom of Heaven which is "not of this world."  Where is it?  There's a big universe out there, and how do you get there?  Up.  Why is that hard to comprehend or wrong?