To a certain extent, you can contrast aspects of this to the coverage of the birth of the "Tea Party", which seemed to start with a host of generally focused messages, bus tours, and press exposure, even while the actual number of people in the crowds were rather lackluster. And yet, despite connections to conservative political organizations like FreedomWorks, many in the media characterized the Tea Party Movement as a grass roots effort.
Part of the problem -- and it's inherent to the nature of astroturf -- is that it can be difficult for people to tell the difference between a grass roots voice and an astroturf voice, between an authentic crowd and a sponsored crowd. While there are organizations and sites that attempt to drill down into media campaigns and look for astroturf roots, even if you're interested in those kinds of issues, you probably don't go check those sites regularly.
In today's media culture, it's easy to forget what a crowd sounds like. From television shows like American Idol to the musical world of Autotune, modern music is usually harmonious and on-key. Even crappy-in-real-life performers can go into the recording studio and receive enough audio processing to make them sound like they have talent. Modern audiences expect harmony. They expect orchestration.
Contrast this with the Jefferson Airplane. Jefferson Airplane songs often sound like a collection of dissonant voices trying to shout over one another. They are loosely harmonious yet packed with discord. On occasion, they seem to come together to a chorus, but even in those moments they're clearly composed of separate voices. But don't think that this is simply the result of a bad sound system or poor live performances -- listen to several live performances and you'll see the same songs performed in a similar style. This is protest music. This is the sound of a crowd. This is what grass roots sounds like.