The Dollar is a regulated currency... that doesn't seem to be working out all that well.
I'm not going to argue the merits of the position. This thread is about how to talk to OWS protesters about bitcoin.
Ok... so tell them the truth, don't invent some convenient fiction.
If make shit up about Bitcoin, they're not going to like it once they find out how it really works.
If you explain that a currency that has been tightly controlled by the central bank/federal government since 1913 has lost 95% of its value, and that Bitcoin offers an alternative, then maybe they'll come around.
Cast a wide net, some may not be at all receptive to the idea... it's probably best not to bother with those people. Make an announcement like "anyone who wants to learn about a form of money and exchange completely separate from any bank (or government), meet at X at Y o'clock".