"A hybrid card needs to be something either monocolor can do."- Which is precisely why hybrid should *not* function as you suggest in Commander, because Lorwyn and Shadowmoor are full of cards that break this rule. Spitting Image is not a card you could print in Mono-Green. Augery Adept could not be done in Mono-Blue. Baleful Liege is not a Mono-White card. Duergar-Hedge Mage is not a Mono-Red card, etc. They are functionally multicolour cards, and should not be allowed in 1-colour decks in EDH.
A few individual card mistakes do not justify having a format differ in hybrid usage from every other format in the game.
Should Commander not allow red cards because Chais Warp exists?