The reason most people believe height has a lot to do with strength is correct only to a point. The main concept that you should think about is the system of levers. Usually, people who are taller have longer arms. Since the shorter person usually has shorter arms, he or she has a greater mechanical advantage to lift the desired weight. A better comparison is to judge by relative cross sectional muscle area (muscle mass). Regardless of height, people that have a cross sectional area of muscle relative in size to each other usually posses the same ability to lift a similar amount of weight. Alot also has to do with genetics and muscle fiber types. I wouldnt worry too much about this whole ordeal of height and strength. Its good to understand the physiological concepts but your time is better spent focusing on making the best of your training, nutrition and rest.