bad big banks?

Someone sent this link to my junk email list at work, along with a rant lamenting evil big banks. The website actually proposes an interesting idea:

The fastest way to kick-start the shift away from a centralized economy is to stop financing the big banks—and through them, the activities they are financing—and to switch your bank deposits to a well-managed, community bank or credit union. In fact, it's the single greatest point of leverage you have as a consumer.

Considering I know little to nothing about finance, business, or the practical aspects of the economy, I'm left wondering whether there is any truth to this statement. Should I stay away from big banks? I have used Bank of America for a number of years now, for all sorts of services. I've never had any problems and they make banking very convenient for me. It is this convenience that has prevented me from changing banks. Do I have a moral obligation to change to a smaller bank? Would it be better for the economy? If so, I'd probably change banks. That said, part of my intuition says that this is just reactionary opposition to large corporations and the global economy. Can anyone fill me in?