I don't want to come across as a defender of the TSA's policies, but this is one area in which I wonder whether passengers overstate their case.

In my experience (since you asked), I have never had an item "confiscated" by the TSA, but the only "prohibited" item I've attempted to take through the checkpoint has been the forgotten bottle of water, which I don't mind relinquishing.

If it were an item of consequence (something expensive and/or important), I'd certainly insist upon having it returned to me so that I can put it in my carry-on and have the bag checked, but I prefer to do this before reaching the checkpoint to avoid the hassle.

I'd be most interested to hear from those who tried to pass through the checkpoint with an item that the TSA prohibited but were not allowed to go back and check/store/dispense of the item, because that clearly fits the definition of "confiscated."