Glenn Beck still maintains that the rally was not political in nature. However, keynote speakers such as Sarah Palin and Alveda King showcase well known conservative politicians tend to paint a different story to Beck's adversaries.
In addition, various Tea Party organizations and the AFP (Americans for Propensity) arranged transportation to and from the rally via buses. The very participation of a political organizations is looked at as some form of indication that the motives were political for the rally.
In addition, Glenn Beck and his "followers" as they are called in the media are against the government paying for things such as a transportation system. Many of those going to the rally used the metro system, which some point out is hypocritical given that Glenn Beck is against socialism and social programs.
Of course, these arguments may be a bit overdramatic. Public transportation is needed, and just because an organization provides a few buses doesn't mean that an entire rally is politically motivated. The premise of the rally was to bring America together, and for that the attendees are not hypocritical at all.