Not sure you understand how this works. To find a K/D, you find the kills and divide by deaths. This works for the global K/D as well. You add total kills and divide by total deaths. You don't average the KDs themselves. It yields inaccurate results as you noted with average of best possible person (infinity) and worst possible person (zero). Infinity / zero = zero. Hence Zero would be theoretical k/d. Impossible and wrong. Take total kills of all players, divide by total deaths of all players. Should yield 0.99 or so when you account for suicides.