Of course you can blame the American people for the Republican congress. And you should. We’re (writ large) responsible for those we (mass-plural “we”) elect.
You can’t blame the American people for Sarah Palin because the American people actually denied her an elected position of power. Any power that she has is due to individual or corporate actions, and you should blame her directly or blame those individuals who have handed her non-political power.
Yes, and there are differences between individuals in a group and the group.
However, if the country is a functioning democracy (like the US and Israel both appear to be), then the people as a whole are responsible for their government. They put them there. You can also blame them (as a whole) for the actions of that government. But only as a whole. You can’t (or at least shouldn’t) blame an individual, because that individual person may have voted the other way.
So yeah, the American people are responsible for the NSA’s practices, the Iraq invasion, and any other action that our elected government has taken on behalf of the people. The American people are CERTAINLY responsible for the GOP/Tea-Party Congress, and we’re responsible for Obama. That doesn’t mean that you can hold Tin Wisdom or Dave Markell or Timex individually accountable though.