I can't completely agree, but it's a fairly well-reasoned ramble. What you fail to realize, shock, is that a lot of us know things aren't that bad, because we've lived lives that, really, haven't been so bad. They've been pretty good. Stuff has been status quo and pretty easy to swallow. But those times are rapidly going down the toilet, and the standard of living we've known is going to disappear, in large part due to the corruption, ignorance, or greed of people who've massed more power than they ever should have been allowed to have. So yeah, things are pretty bad in that light, and they only get worse when you start considering some of the sweeping changes which could theoretically occur due to stuff happening now that's never had the context of the world we live in today. You said it yourself: much has changed. There have been technological and social advances (some I'd be hesitant to call positive, but your mileage may vary), and the world community is in a very different state. Things that may have happened many times before in history may now have entirely different effects, and some of them are pretty scary.
So granted, the media loves to scare people, as do politicians, and those two groups do have their hands in a lot of the bad shit happening to us now, one way or another. But just because some are exaggerating or playing something up doesn't mean there aren't things to be well and truly scared of. And really, just because something's happened before in history certainly doesn't mean you want it happening to you.