From the Asparagirl blog. The same questions I have been asking also occurred to her:

Nearly all--95%, I'd say--of the people there were quite obviously Iranian exiles. And where, I wondered, were all the other non-Iranian American protestors, shouting in support of nascent democratic movement against a brutal theocratic tyranny? Where were the protests from ANSWER and Amnesty International and other human rights groups? The ones who paraded and yelled so vigorously about a certain country just next door to Iran, saying something about human rights and oppression? Whose solipsistic, self-congratulatory, often logically mangled signs and banners I can still see in my head, even had I not documented them with photos?

Needless to say, they didn't come. And I hate to say it, but I doubt they ever will. No rock stars or country stars or actors will speak out for the Iranians. There is no glamour for them here. When the subject was "we don't want a war", I could see, though not agree, with its simplistic appeal, because hey, who actually likes the idea of war? But when the subject is "we support democracy against tyranny", which has the same simplistic, knee-jerk appeal, the reaction is shrugged shoulders and maybe a "yeah, good luck with that".

Ken Wheaton at the blog As I Please has more on that very subject.