No, this isn't Stalinist Russia, but the question is, if we continue down this route, could we BECOME Stalinist Russia, or something similar? I think that the consensus on that is definitely yes. Intimidation of journalists, secretive detainment, interrogation and assassination, the USA is definitely headed down a dark path.
However, I want to emphasize that if you invoke the slippery slope argument, you better realize that the slope is very very slight. Instead, I think it makes sense to talk about things on a case by case basis. For example "NSA does more harm than good" is a more rational and direct argument than "NSA is the coming of Stalin to America".
On top of this, there is the big picture: the US's largest export is weapons. This leads to a lot of people hating the US, which leads to terrorism. That leads to counterterrorism in the form of drones and spy agencies. Even if the US made nice with the various governments around the world that do not like us, we would be stifling our main export, so there is no incentive to do that.