The problem goes deeper than fear, though. Think of all the dissidents and critics of Islam from outside the community whose names are known and who appear on national TV and radio broadcasts. Think of resistors and dissdents in the Soviet Union and Nazi Germany.
Sorry, I think that the 'moderates' are a block of 'inactive' potential jihadists who, when it's time to get more 'devout,' tend to fall more in line with jihadist GOALS if not METHODS. Then when the Islamists become a powerful political party or lead a certain social or paramilitary movement, the 'moderates' fall in line with whatever the 'strong horse' is in that population and don't resist because they believe that the jihadists are, by and large, living the exemplary Muslim life.
Notice that the only anti-terrorist protests happen in Muslim countries when the jihadis kill Muslims. Some regions or populations are more or less sympathetic but I think we'll be waiting a long time to see anyone but intellectuals and pundits speaking out as Muslims against terror. No grass roots movement will be happening in the mainstream sects (Druze and Sufi don't count.)
You are right, if they are not actually "good" people, these silent Muslims, living in fear like some poor people in gang areas of the city (who "saw nothing, Officer"), then they could be the moderates of whom you speak. Believing in what their brethren are trying to do and merely wincing when so many infidels have to be killed to get the job done.