It has struck me for sometime now that a good % of US-made film and TV has a theme of a totalitarian nation-state, the armed struggle against such a dictatorship and "it's all a conspiracy".

I enjoyed the X-Files until they went into conspiracy mode. 'Revolution' is a more recent TV series, which after a few episodes became so predictable. The TV series 'Person of Interest', written pre-Snowden is very clever conceptually as a drama, but again there's a nation-state conspiracy.

What impact does such a constant theme in imagery have upon the general population?

Here in the UK there must be one if not two such TV programmes each day.