The purpose of keeping information from general dissemination is -- or at least should be -- to prevent the information from benefiting those who would do harm to society. For example, if the police are aware that organized criminals are using a particular location to discuss their murder plans, and they can plant a listening device in that location, allowing the general public to know about the device will defeat its purpose. The criminals will simply find another, more private, location to hatch their plan. In situations such as this, secrecy is key. Secrecy is a problem, on the other hand, when it is used to prevent the public from uncovering illegal activity. Unfortunately, many people assume that information is kept secret for the latter reason, when in actuality it is for the former.
Please keep this in mind when seeking information from the government. For the most part, the people working in these areas are genuinely motivated by a desire to help their fellow citizens, by stopping those who would seek to harm us. This includes most police officers and intelligence professionals. They generally have no interest in your personal discussions about what to make for dinner, and would rather focus on discussions about criminal activity. If you request documents about a particular government program and are denied because the information is classified, do not assume that the program is targeting you.