You don't think of these matters beyond the politicially correct. What ultimately defines the religion? The creators?
Christianity: Jesus was a pacifist. He preached "Turn the other Cheek." He preached equality and love.
Islam: Muhammad preached much the same thing. However, he was a politician, a general and a soveriegn. He authorized the shedding of blood and justified as a defense of Islam.
Now, it is entirely appropriate to label Christianity corrupt because history has shown Christians behave very unlike what Jesus prescribed. The Crusades and so on were not in keeping with Jesus' example. But what about Islam? Are Muslims really that wrong when they shed blood in the name of Islam as Muhammad did? Can we call Islam corrupt? Or is Islam exactly what the creator prescribed? People after the fact have interpretaed their religions in accordance to local tradition or personal want and desire. But there is no arguing about what the creators had in mind for their movements. The Bible came later and has been accepted to have been written by multiple men and women across time. However, the Qur'an has been accepted as absolute word of God handed down to Muhammad through Gabriel. Killing in the "defense" of Islam is very Muslim.
What you call corrupt Islamic radicals, I call Muhammad's followers. Those Muslims who choose to prescribe themselves a more Jesus like Islam may be the corrupt (or weak) ones. I would call them necessary reformers. All religions must reform. But Christians have been struggling to turn Christianity back into what Jesus had in mind for centuries. What are Muslims trying to do?