Just because Paul proclaimed the foolishness of preaching to be superior to the wisdom of men doesn't mean that church foolishness is divine in nature. In fact, the real foolishness of Jesus is as foreign and foolish to most in the church as it is to the majority of mankind in general. Jesus' message of divine love and forgiveness as proclaimed in the Sermon on the Mount and the Golden Rule is rarely central in church teaching. They are too intent on proving that compliance to their doctrines is the necessary foolishness about which Paul spoke.
No, church foolishness, for the most part, is actually old school foolish, being nothing more than a rehash of Old Testament law keeping and completely ignoring the counter intuitiveness of Christ. When the supposed divine truth doesn't stretch your mind way outside its normal bounds, then that "truth" sounds too much like the wisdom of men which Paul implied was the real foolishness.