Everyone has their beliefs, I was driving tractors on my mothers family farm in Finch Ontario when I was 9 or 10. Dad was a motorhead, rebuilt cars, motorcycles, snowmobiles, whatever. I hung around him every waking moment so I was riding or driving whatever he was working on from a very early age.
Those times were different, not careless or wreckless, just different. I raised my daughters to be the same way, my 23 year old daughter has put some men to shame when parking their horse trailers, recently she parked a trailer for a gentleman who was experiencing difficulty. They can ride bike, drive tractor with trailers full of hay, drive truck and to look at them dressed up you wouldn't think either of them would be inclined or interested in doing any of it.
As parents we all have our personal beliefs on what we need to do to prepare our kids for life, sometimes that involves risk. I'm not supportive of needless risk but I'm not in favour of dance class over motocross either (nothing wrong with dance class either, great exercise).
As far as the buddy seat is concerned, for my kids I taught them to drive when they were old enough to reach the pedals and had the awareness needed to drive. If I had owned a cab tractor I would have allowed them to ride with me, all I had was an open station so that wasn't possible.