If you are worried about human rights, freedoms, you should worry about USA as well. There are enough ways to circumvent or interpret the law to suite the need, like border search and seizure few meters outside the constitutional zone applied to American citizen.

I have seen enough instances when first amendment rights are also bulldozed (still there is hope as someone emerges to preserve it). Arresting assange in UK trying to extradite him to USA, Snowden are just the tip of the iceberg.

Constitution is not absolute but a moving target with time. It requires a good faith constant effort to keep it and it's spirit alive.

I believe having a democracy does not guarantee it will remain same. The best example is India, where the current govt is bulldozing the constitutional spirit with amendments to turn it into Hindu nation and make it more like China where govt has absolute control. Anyone Who criticise the govt will be termed terrorist.

Both USA and China have their own set of good and bad, can't paint either with a broad brush.