Knights were introduced to change how people do the encounter. Tell me, regardless of strategy or 'cheese' or whatever, was the method of clearing the encounter changed? The answer is yes, so Bungie accomplished what they wanted. Just because some people were too stupid to think of it doesn't mean Bungie didn't intend for the strategy to be used. Regardless of strategy, the drinker knights are dealt with as intended (you prevent them from stealing the bombs).