This is an outrage! There has long been a debate about whether the TEA Party movement is really an independent non-partisan affair or if it is simply an adjunct of the Republican Party. This is a complicated matter due to the spontaneous and decentralize nature of the phenomenon. In some communities it is more the former, and in some it is more the latter.
I think the trend has been toward the movement being co-opted by Republican centric (although not necessarily Establishment oriented) forces. And I think this largely has to do with those groups having the funding to provide higher level organizational structure to the local level.
This episode tends to confirm this trend although the message is decidedly mixed. Libertarian Alex Snitker is being allowed to speak, for example. Glenn Lord, who seems to be speaking for the group, is clearly imposing his own personal beliefs about the utility of third parties on the TEA Party as a whole. His e-mails attempting to justify the exclusion of DeCastro strike me as unprofessional. If there was a legit reason to deny him a speaking slot due to time, (Which I highly doubt. If they wanted to make time they could.) that would be one thing, but on what grounds is he also being denied a table? There isn’t room for one more table? The reason from Lord’s e-mails is clear. Lord doesn’t want him to have one because Lord doesn’t think third parties are useful.