Who said anything about 20 km/h on an open highway in dry conditions. That wouldn't be driving to the conditions either. All these contradictions just to try to prove me wrong. I'm certainly not arguing over what you choose to do. I'm simply pointing out that defensive driving isn't the stupidity that you claim it to be; I'm sorry if you're not open to having your misconceptions challenged.
As I said there are plenty of course out there teaching what you believe is best. No need to prove me wrong, just go out book one. .
I said it about 20km/h etc etc.

See
here.
20 km/hr would be driving to the conditions if there was a risk of a tree branch dropping down on the highway in front of you. I happen to be in correspondence with the Tas roads dept about trying to get some dead eucalypt branches taken down that are overhanging way over the highway where I drive. But there, people still drive pretty normal highway speeds (~80km/hr), which might be expected as people don't appreciate the danger of a dead eucalypt branch, especially as its amongst some live eucalypt branches which hang horizontally over the paved surface (which are a danger in themselves).
So, if they are driving normal highway speeds, and when the branch finally gives way onto the road in front of them (and it will give way sooner rather than later), the natural reaction of the on-coming driver will be to swerve and slam on the brakes. Likely a skid if they hit the gravel verge and/or over-correct. See how it might happen even if 'driving to the conditions'? An inexperienced driver would be at even greater risk.
At these times I hope the driver will have some skills in avoiding a lethal skid etc, notwithstanding they were driving to the conditions (that they were aware of).
I do happen to know something about defensive driving - I went in and discussed my nephew's course with the RACT people, and I've done maybe
three courses :shock: myself over the years, put on by my employers, because as geologists we drive on some dicey road surfaces at times, not to mention driving in third world countries where the greatest danger is the other drivers.
No, I'm not just trying to prove you wrong. And I didn't claim that defensive driving courses were a stupidity - please go back and check if you like. (Why would I go out and get one for my nephew if I though that?) I merely put a post up with a trivial anecdote and commented that I thought not teaching skills on how to manage a skid was dumb. That's all. Later I said that what I was describing was what I wanted for my family members, but "YMMV", meaning I knew that we would likely disagree and wanted to leave it at that. But on it went. I wasn't trying to convert you, nor did I think I needed to put my life experience on the topic in the post - it was just an anecdote, forsooth. I reckon I do know more about defensive driving than you; its a vital part of my work, and I get all the kids in my extended family trained in it, but that doesn't really matter a fig here.
I, and I expect everyone else is bored to tears with this.