Judaism, Christianity, and Islam all have their moderate, benign sides, but as is true of all things, religious or not, the loudmouths who are jockeying for attention, power, domination, influence, status, etc., are the ones who are heard and seen. In other words, grandstanding works. These know-it-alls gather power within a small, loyal clique, and moderates and liberals better shut up and hide in the shadows when one of these waves of fanaticism sweep through, and even in the best of times they are marginalized, regardless of who outnumbers who. The vicious and brutal usually win.
This is why you won't see many moderate liberals leading mass movements. They'll always timidly try to blend in, not be conspicuous, tbuild consensus, in general be reasonable. The aggressive ones elbowing their way to the front of the line get the bullhorn. It's always been that way most places, especially the Muslim world but somehow, for a while at least, the U.S. had a reasonable balance; not that Jimmy Swaggarts not right around the corner.