A strong case could be made for that.....the tea party is not a unifying force...it has split the Conservative element of the Republican Party and that was a key factor in Romney's loss...The Tea Party had considerable influence in the 08 primaries but went along with the nomination of Romney...a sure loser. That tells me the Tea Party could very well be a tool for the democratic poarty.
There is no such thing as the Tea Party, its a contrivance of the right.
The TPM is in essence disaffected republicans and partisan conservatives seeking solace after losing the WH in 2008.
The TPM is made up mostly of the Old Bush Base, social conservatives, Christian fundamentalists, and the radical fiscal right.
And unfortunately there is a significant racist component to the TPM, the evidence of that has been provided by the OP.
But yes, however inadvertently and unwittingly, the TPM has succeeded in benefiting the democrats. During the 2010 midterms, for example, TPM candidates cost republicans Senate seats in Colorado, Nevada, and Connecticut, as well as the governors races in California and New York.
In 2012 TPM candidates contributed to the republicans failing to take control of the Senate, indeed losing seats in that body, as well as costing republicans seats in the House.
Its certainly correct to say that democrats would like the TPM to stick around, particularly if their candidates are going to continue to make reference to Second Amendment solutions and legitimate rape.