I don't really get what the line of argument is here, exactly. The CIA & FBI engaged in massive abuses in the past, including psychological and biological experimentation on unwitting US subjects, so therefore we should be blasé about their ongoing mass surveillance program (which, incidentally, has the potential for much more wide-reaching political and societal damage than anything that's come before it)?
I guess one could also argue for calm on the basis that the Stasi once existed and these days East Germany is an okay place.
And the solutions to these issues are perfectly well known: the intelligence agencies need to be curtailed and reined in, and their ability to indefinitely store massive reams of data about every private citizen brought to an end.