Then how do you explain the fact that more self-identified Tea Party members prefer Perry over Bachmann, Cain or anyone else in the race? Are they not really Tea Party members unless YOU deem to be "true" tea party members? What ever gave YOU the ability to read people's minds and determine if they are conservative enough? Or are you just a legend in your own mind?
Perry has no Tea Party chapter endorsements! Not even from his own Texas backyard. Hummmmm, I wonder why???
Tea Party has the name it has because it is fundamentally an anti-tax movement. That's why tea bags were used in the initial protest, as a hark back to the Boston Tea Party - an anti-tax protest. That's why the first big rallies were on tax day, April 15th. That's why TEA stands for "Taxed Enough Already".
Notice what's not there. No social issues whatsoever.
Now, the name can be stolen and misappropriated until there is a great mass of people falsely labeling themselves as such, but the bottom line is that the sentiment that motivates the Tea Party (pre-co-opted version) cannot be harnessed by culture warriors of any stripe.
So to answer your question, what gave me the ability to tell one from the other? The fact that I have been involved in this since Santelli had his famous rant on TV that encouraged everyone to send in tea bags to their congresscritters, an event that Perry supporters probably aren't even aware of.