If by SC he means Starcraft, it's completely true and not at all picky - one marine from one player may be tougher or do more damage than another marine from a different player because of weapon or armour upgrades, despite looking identical. UI is ok for describing what a unit can do if it's not obvious from the unit design and never changes (for example, that a unit is amphibious); but it's not ok for describing differences between identical looking units, especially if such differences can change over the course of the game - such differences should be immediately visible, or else you have to constantly re-check units by hovering over them. SC2 improved on this IIRC, but I haven't played it much. You are quite right though that Starcraft is not alone in this. If he means Sup Com, the only instance of it is some of the commander upgrades. Given the importance (and singular nature) of the unit, it's a fairly acceptable exception.