Swift actions shouldn't be allowed in charged items. It disrupts my sense of balance. Kind of like Quickened True Strike is unbalanced in an item, especially a multi-charge item like a wand.
"No gestures or spell finishing is needed, just a special knowledge of spellcasting that an appropriate character would know, and a single word that must be spoken."
It is not a function of the spell being placed into the wand, it is the function of wands. You must state a single word in order to activate the wand and that is (typically) a standard (triggering) action.
In the case of swift (or quickened) spells, the spell level is higher in order to get the spell cast faster. Note the word "cast". Activating an item is not casting. The result of the spell is the same, but it does not use the same "casting" or activation method.
To me, this is no different than the rules making the Quicken Spell feat "useless" for Sorcerers. It's a WotC ruling on how the game works and the counter argument for Swift spells in Wands (or Scrolls) does not have any balance reasons for it to be different.
Rules are typically only bad if they are unbalanced, too complex, or not useable in the game. This rule is none of these, hence, it is not bad. It just happens to not be what you expect in terms of consistency.