Big statement Dan, so hundreds of Governments and people around the world have got it wrong !
Safer is a relative term. Shorter stopping distance in the cold and damp at 3c? Yeah, sure. More grip on cold compacted snow/ice? No chance, you cannae break the laws of physics Jim. Put an average driver who knows nothing about tyres in a Ford Focus with summers on and an Elise with winters on and see which one he bins first. Are winter tyres safer than summers on a dry day at 7c? Nope. There's so many different circumstances and variables that it's impossible to say that winters are simply better than summers from October to March. It implies a sense of safety where one might not actually exist.
In certain conditions, winter tyres offer certain advantages over summer tyres, especially this time of year. But 100% safer? Sorry, I don't feel that's a correct statement to make.