Because (in NL) you're supposed to wear a full protective suit with padding and a helmet, or get a significantly worse ticket and potential loss of head/limb.
I used to think that too until a friend pointed out to me that I might bog down the healthcare system with injuries that could have been easily avoided if I had.
On the one hand, it's a victimless crime, at least roughly. On the other, people have been shown incapable of making the obvious correct decision on their own.