Well, whether the Rama Setu was a man made object or not is not the question. The question is that of the belief of countless Hindus. By destroying the Setu, one would be hurting the sentiments of the majority community. Proof does not exist does not mean events did not occur. What if it is discovered tomorrow that Ramayana was truth by some scientific means. Can the Rama Setu be re built? People in India, who live in places that were on the path of Rama to Lanka believe strobgly that Rama passed through their place and regard it highly. Sometimes, efficiency of the modern age must be given up for the beliefs of people.