I did not really understand the astrological explanations given in the documentary (there are others around too so I will look into these), but just a couple of years ago, 2012 meant end of the world, now it meant that there would be a definite change in human consciousness, due to the current events building up. People were seeking a new shift in paradigm, the living together in harmony of earth and matter and species. There was chat on magnetic poles reversing, planets aligning, but also the event where there will be a huge sunburst during 2012 which will knock out all or most of human support systems (a few years ago, there was a sun storm that did this at a small scale and caused blackouts).
But I agree, it is another New Age thing to latch on, but it is probably the largest one bigger than Y2K, because it is based on the Mayan calendar (history repeats), and there are other links to other almanacs such as the Tao Te Ching. These New Aging folks also try tying up Mayan philosophy with Vedic (yuga) cycles and ages talking about the dawn of the Golden Age as we move into the Age of Aquarius (which happens to be a song I heard when I was young and had no idea what it was about until now !).
I think BKs or rather BKWSU are very careful in using 2012 for its cause and announcing it publicly. As it would end up being another "1976 fiasco" for them. And if something does happen
then there won't be anyone around anyway for them to say "I told you so ".