Fatboywings,
Your dilemma is exactly the topic of a recent discussion I had with the deparment, namely inconsistency in interpretation of what are and what are not prohibited items. No one in this game is perfect, some will use common sense and others will err on the side of extreme caution and until every conceivable physical item is listed in a table somewhere, we are going to be faced with situations such as you experienced.
My advice, Print out the latest table of items from the ATSRs and have it handy. Ask to speak to the security supervisor if you disagree with a screening officer. Sadly though you will be pushing the proverbial uphill with a pointy stick as they will stick together in order to save face.
As an aside, I have been flying with a pair of noise cancelling headsets for about the last 4 years. On a recent flight PER - SYD during the cabin prep for landing the FA looked at me, went to the CM for a few words and then came back and said, I'm sorry sir, you will have to turn those off for landing as they are noise cancelling and you will not be able to hear our instructions in the event of an emergency. Errr... don't your instructions usually get passed via the PA anyway?
Point is, it's no good arguing with someone who has probably less understanding than you of the relevant rules.