teabagger is a derogatory term as well. The right used it first - they wanted to 'tea bag' the lib senators and congressmen spending all the $. Of course, Maddow was very fast to say "well, they want to use the word - let's label them with it!"
That didn't end well, so they quickly stopped using 'tea BAG' and started using 'tea party'.
But it was the right that used that word first. The 'tea bag campaign', etc came long before the tea PARTY. Remember when you were encouraged to mail tea bags? And some guy bought a million tea bags but wasn't allowed to use them, etc?