Many of us (moderates) are plenty passionate. Many of us simply use logic to apply our political passion to issues (I know, novel concept) as opposed to strict ideologies, out-of-context sound bites, party alignments, and slogans.
This brand of passion, admittedly, tends to draw less public notice as it involves less drama and is harder to label with an encompassing moniker, but that doesn't mean it's not there.
If I'm being too literal and your intent was to state that moderates are harder to identify and less likely to have the unified voice than are the extremes...well, that's obviously true.
If you're implying that there can be no successful politics without extremism (and the pandering that goes with) then I am tempted to suggest that you are perhaps more cynic than skeptic...or that I'm off my rocker to think there's even a chance of significantly improving the political landscape. I'll have to consider this for a while...