1) In order to read/parse the config in a meaningful and reliable way. It's a shame if we have to search for substrings in classnames.
2) If the DisplayName of some ammobox says "Explosives [CSAT]", then that should tell you something. Clearly ammoboxes are linked to factions, and therby to sides.
 Well, I've just checked and it certainly was like this in ArmA2, so I guess it was always like this? Was there ever a good reason for this? Like making AI not target/prioritize those ammoboxes over enemies that dare to shot back or something? Just curious... :)