There is a troubling problem with any increase in government firepower: be it heavy weaponry in our police stations, advanced monitoring capabilities that can be used on the entire populace at once, or drones that can hit targets on the other side of the planet.
What happens when these weapons are used against us?
Let's just assume for a minute that our government has our best interests in mind and is basically benevolent. With a database of potential intelligence against every person in the US, you create a dangerous situation: what happens if the Chinese or Russian government has covert access to this system and strategically leaks information with the purpose of influencing US elections? This feels completely plausible in my mind: there are real risks to having so much information available in one place. The fact that the controls were so weak to begin with makes me almost certain that foreign intelligence has continued access to these databases.
Every weapon we develop can potentially be used against us. In the case of cyberwarfare, those weapons can be used against us without our knowledge. The scariest part of Snowden's leaks is how awful the government is at technology: most people on the Internet were pretty sure the government was spying on everyone anyway. Geopolitics gets messy, so that stuff is forgivable. But when a single government contractor is able to walk away with so much information and they don't even know what he has?
This is probably already happening, though it isn't China or Russia.