Early tests were done above ground - partly because we knew no better, partly because we didn't know if they'd actually work and partly because, them being bombs and all, we wanted to see just how effective they'd be at destroying cities and incinerating people. Later once we'd put two and two together (this took one hell of a long time) we decided that it would be better to test the bombs underground. The fact remains that a lot of the crud that's killing people today was released by our and other Governments, oh and our taxes paid for them to be able to do it!
In terms of destructive power even the nukes we have pale into insignificance beside a really good volcano or better yet a plummeting meteor, but it's the insidious nature of radioactivity and the really nasty way it alters our bodies that does (and should) scare us.
Today I don't think enough people are scared enough of nuclear warfare. It's all a bit remote. The Cold War's over. It's the terrorist who scares us now. The generation that lived through WWII and Korea and came home to Civil Defence and the Cuba Missile affair - they were worried. That's why you saw little old ladies from the Home Counties at Greenham Common. Call it a Cruise Missile and maybe people will think it's sponsored by P&O. Call it what it is, the modern day equivalent of the Nazis' V1 only capable of killing 10,000 people from 600 miles and they might not be so happy.
That said - shoot me with a clean, traditional, environmentally-friendly .303, or 7.62mm, or mortar bomb, or grenade and I'll be just as dead - it's simply that you'll be able to handle the body immediately afterwards without adopting a radiation protocol.
Please pardon the length of the rant - I make no apologies for the tone!
Man is the only animal who can blush - or who needs to - Mark Twain