Yeah, imagine how paranoid we'd be if someone had used dynamite to blow up an entire school building full of kids. :(
Oh, wait, someone did, in 1927, and nobody launched a generalized war on sanity as a result.
There must be something else different.
Media. Back then news spread slowly.
It also seems bullying has grown to astronomical proportions.
Hasn't changed, people are only aware of it these days.
No, the paranoia and cocooning has been building much longer than that. After the wild period of 1960-1989, the pendulum has swung the other way and America is reliving the straight-laced 1950s.