Which is more dangerous radical islam or radical secularism?

Radicalism is dangerous, whether secular, Islamic, Christian or Hindu. Radicals have their own agenda of self-aggrandisement and then manipulate someone-else's belief system to fit. The 20th century saw more people die at the hands of radical secularists than all the people who have died of violence before or since throughout recorded history. If Bin Laden suddenly became a Christian fundamentalist or a gay militant, he'd be just as dangerous.