Always seemed like a reasonable policy to me. The people operating heavier vehicles have a higher inherent responsibility to operate them safely.
I found it very enlightening to learn that even in the Netherlands, there used to be car culture similar to here, and it took the death of some children, and a grassroots campaign, before meaningful change began to occur.
There are many lessons to learn from the Netherlands with regard to bicycle infrastructure, and for our sake I certainly hope it doesn't involve the death of children.
It doesn't have to: https://en.wikipedia.org/wiki/Cycling_in_Copenhagen
Like the Netherlands, the city of Copenhagen has a highly evolved bicycle infrastructure, but the catalyst for change was the dual oil crises in the 1970s which led to car-free Sundays and other oil preservation measures. People disovered that they actually appreciated the lack of cars and many started using bicycles as an alternative. This resulted in a grassroots movement campaigning for bicycle infrastructure in the city. The municipality caught on and today almost two thirds commute by bicycle.