Your opinions are valid... But that statement above generalizes many, but mostly to those who will be ignorant. Just my opinion, it depends on the mentality of the rider.
With my mind set, I think there is no in between, either your capable of riding a bike, or you're not.
If you're not, doesn't mean you can't, I just think you increase the risk to yourself and others around you more than what is acceptable in my opinions. Whether you are new or not, doesn't have any effect on it.
With bikes, or anything else in life, there is always risk. It's just how each of us reduces that risk, no matter how long we have been riding or what our skills are.
Again, not saying all you're opinions are incorrect, hell, I think all of them are definitely valid. We just think differently coming from different backgrounds.