@cale: In the UK you can only drive automatics if you pass your test in one. Pass in manual and you are ok in whatever.
I've only ever driven automatics a half dozen times amd have never felt safe doing it. I need a clutch.
Were all six times during incredibly adverse weather conditions, or recklessly high speeds? I'm not aware of other situations where the differences between automatic and manual are particularly relevant to your safety.
Engine braking is one such circumstance where you are certainly 'safer' with a manual, everything else being equal. At least in Scotland, where everything is so hilly that it's one of the first things you get taught, but I gather that isn't the case everywjere. You can't really do it with an automatic, obviously. Going up steep hills is also a bit easier to do safely as well.
I assume Americans mostly drive automatics because they have two types of road - long, empty straight roads that go on for 100s of miles, or choked-up inner-city traffic at 2mph. In both cases, manuals are a nuisance. In most cities in Europe (even the less 'progressive' UK) there is no need or desire to do much driving in city centres very often unless you are flamboyantly rich and like walking long distances from a parking space you had to kill someone for. Also our roads are the bendy, hilly pleasures Americans only see in video games.
I can happily drive both but an automatic is always less engaging and more frustrating. The automatic I drive most often has dangerously slow acceleration.