White - check
Conservative - check
As we have discovered, those are the only two criteria for one to be considered a racist in American society now. Therefore, the answer to this question is "yes," without a doubt, tea partiers must all be racists.
There is no way this many white people could get together without their default setting of "hatemonger" showing it's ugly face and making itself the underlying theme of a movement. There is no way they could all really be concerned about excessive spending, big government takeovers, coming hyperinflation and increases in taxes.
It's just racism.