Without getting too complex, it has to do with the tack length of the road bike. All road bike are inherently more twichy because of the head tube angle relative to the position where the hub is. Imagine drawing a straight line directly from the hub down to the ground. Then imagine extending the head tube line down to the ground. The distance between the two lines affect the twichiness of the bike. That's the reason why a road bike is so reponsive but a tt bike is not.