The answer is actually because we spent several years with the entire country dedicated tona total war effort in the face of an enemy that was devoted to our total and absolute extinction and subjugation.
Following that rather than returning to a peacetime country and disbanding the associated military structure it was instead repurposed for a cold war in the face of another enemy that had sworn themselves to our complete and absolute destruction and which had the capability to do so. In the face of such constant risk of extinction almost any measure was seen acceptable to counteract the threat.
However after about 60 years the threat disappeared but the massive institutions built up to combat the threat then needed to continue to justify it's existence as careers and lives had been built upon counteracting the Red menance. Unfortunately these institutions did not cease to exist and continued the same tactics that it was profecient in despite the threat to the existence of the nation.
Lol. Mass spying is far from recent. Mail has been spied upon for centuries in the US. Sending agents to spy on political groups too. I'm never sure exactly when this ideal time was, that time before government got evil, but I suspect it never really existed.
I believe it is not about the means and the tooling. Systemic problems need to fix the system, not various outcomes of such problems. Assuming we are talking about democracies, I guess it is up to the people. If the people do not care, then fine. "Nothing to see here, move along". If this is the case, I disagree with "the people", but apparently that is just me... Or few of us.
Following that rather than returning to a peacetime country and disbanding the associated military structure it was instead repurposed for a cold war in the face of another enemy that had sworn themselves to our complete and absolute destruction and which had the capability to do so. In the face of such constant risk of extinction almost any measure was seen acceptable to counteract the threat.
However after about 60 years the threat disappeared but the massive institutions built up to combat the threat then needed to continue to justify it's existence as careers and lives had been built upon counteracting the Red menance. Unfortunately these institutions did not cease to exist and continued the same tactics that it was profecient in despite the threat to the existence of the nation.
That's basically it in a nutshell.