I wouldn't be such a winter tire advocate if people could be trusted to drive for the conditions. The problem is when, say, 25% of us on the road have winter tires and are going at a speed of 70 km/h. How many drivers with all-seasons will stay at their at their safe speed of 50 km/h (hypothetical)?
In the summer, most are driving to the limits of the driver. Barring unforseen circumstances*, a driver usually knows where their limit is. In the winter, most are driving to the limits of the car. Few people truly understand where that limit lies and how dynamic that limit is.
*being deer, debris, unsafe lane change, etc., which means the drivers capable of 250 km/h when everything goes right still can't safely do so in public.