I dont think these men are insecure about their faith, I think they are the oppisite because, they are showing that they love and have such respect for the prophet (pbuh) that they will go and have a march and a demonstration for what they believe in. They shouldn't be shouting things like 7/7 and 9/11's coming back etc, but it has angered them so much. Islam is a peaceful religion, but people and angry men make it seem violent