Why does the first mandate the second? A private insurer doesn't compel me to do <X>, it just invalidates cover if I don't. I'm not fined for being fat, or eve

Why does the first mandate the second? A private insurer doesn't compel me to do <X>, it just invalidates cover if I don't. I'm not fined for being fat, or even given the bill for my own (hypothetical) coronary, despite the enormous liability that gives the state. As long as that's true, I'd say motorcyclists can reasonably doubt that protecting the state is the real purpose.