Team damage (friendly fire) is a feature of many first person shooters for a reason, it adds very interersting gameplay dynamics to the existing game. The player now has many more obstacles on the map, although a lot of people abuse this feature to harass others, without it all of those other games which will remain unmentioned, and AssaultCube, would not be as fun.
My 2ยข :p
My 2ยข :p