Because a “news source” has recently brought to my attention the fact that the more fundamentalist christians are, the more they are against any form of contraception, and the more children they have. Whereas we, intelligent that we are, realize the horrible problems that are caused by having too many children (both on a personal and on a global level).
This means that 1: social conservatives are reproducing at a much higher rate than liberals (apparently the birthrate accounts for 70°f decrease in “mainline” protestant church membership and the equivalent raise in fundamentalist church membership).
In related news, in the last election bush carried the 19 states with the highest birthrates, and kerry carried the 16 states with the lowest birthrates.
So basically, inside of a democratic semi-advanced culture such as ours fundamentalists are the product of simple darwinian processes which make them historically and culturally suited to become an over-riding majority in a democracy and thus gain power.
Actually, their suitedness for political power is in line with, and probably necessary for, their eschatological aims. They couldn’t bring around the end of the world if their beliefs don’t lend themselves to gaining political power.