There is huge difference in the way Indians perceive terrorism when compared to Americans. Americans easily dismiss govt. efforts such as these in the name of privacy invasion. But, when you are closer to getting your ass bombed by a neighborhood terrorist, then privacy is the last thing on your mind. You will be actually grateful that your govt is pulling all stops to giving terrorist easy options to communicate and escape their radar. Terrorism in India is daily reality. Its more direct. US has not faced a terror attack on its soil since 2001. India, OTOH, faces a huge terror attack every year (remember 26/11 Mumbai), in addition to attacks in Kashmir every other day. So, when Indians look at this issue, its much less about invasion of privacy and much more about security and closing gaps for insurgents (Maoists) and terrorists from across the border. Most of the intelligence attack trawthed by Indian Intelligence agencies are through wiretaps and intercepts of mobile calls between terrorists and their handlers across the border in Kashmir. So, from the point of Indian Intelligence agencies, its very important to intercept RIM calls as well.
When you are faced with fear that the daily metro train you take to office might be blown off or that restaurant you visit for dinner might be attacked by gunmen, privacy invasion is the last thing on your mind. I am an Indian and have gone through such moments in my life. And I very well understand what my govt. is trying to do here!