What about a president 10 or 15 years from now?
Frankly, if you think that in 10-15 years America is remotely likely to be introducing gulags and death camps, then NSA surveillance is the last thing you should be worrying about; Hitler nor Stalin neither had nor needed an effective way of monitoring most private communications to eliminate all resistance and millions of people. If I was worried prospective presidential candidates were secretly plotting to lock me in camps I'd probably support the government going all Richard Nixon and wiretapping the opposition.
The possibility for individual abuse is certainly worth emphasizing, but the risk of systemic corruption is not to be dismissed.
People blame Hitler and Stalin individually, but they were far from the only ones in their respective countries with blood on their hands. A President who comes in and says "I want to build death camps" with no popular support is not going anywhere. But nobody advocating them will actually call them death camps. They get names like "military detention center" or just plain old prison. The people put there get sold to the population as terrorists or violent gang members. The soldiers or police don't contemplate what they're doing as wrong, even if humans die or are abused, because they're "the enemy" and they don't count.
And even if we never make it to death camps, every step on that road is human suffering. Even our existing prison and criminal justice system is an unfathomable catastrophe that people fail to revolt against almost entirely because those with the capacity to make change are not aware of the true nature of the existing system. The entire concept of secret surveillance with secret courts making secret laws can only exacerbate that effect significantly, creating the very real risk that one day we'll wake up to a world vastly different than the one we previously contemplated solely because no one was allowed to tell us about the changes until it had already happened.
Things change. We should measure the poor and powerless of today against the rich and powerful of today, not against the poor and powerless of yesterday.
