I agree with tazi. The TSA has no legal authority to order me to keep my liquids in a baggie once I traverse the checkpoint. Absolutely none. The OP was fed this line of crap by a loser because the OP had the nerve to show up the screener and interrupt the confiscation of the liquids.

As for the OP's infant water: I would have immediately demanded a supervisor and LEO and would have sworn out a complaint for theft. If it's been approved by a screener at the checkpoint, and meets the exception, then its subsequent tossing in the trash amounts to theft. What a worthless piece of garbage that loser is. Professional security? None to be found here.