I think he means beacuse the decks are generated using cards of one of the two elements the enemy has, such creatures with abilities not of their element, mind flyer, gravitron firemaster, anubis, etc, aren't able to use their skills because the AI's elements would just be the element used to summon the creature and some other element.
In other words, many times the creatures with ability costs that are different than the creatures element often can't use their ability because the AI's duo deck doesn't use it.