The public pays for the cost of their injuries, either directly through a state healthcare system or in the form of increased premiums. An insurance company has no way to differentiate reckless motorcyclists who are lucky from responsible motorcyclists.

The cost of the injuries is far less than the same behavior in a car.

A crash on a road will close one or more lanes while emergency services attend the site of the crash, causing congestion

I have only seen this happen once, when a guy did suicide by bike by driving directly into the back of a dump truck doing like 100 on a bridge at 4 AM about a year ago. The bike was ripped in half and the body was so messed up nobody wanted to touch it.

Every other time, someone just walks/drags the bike and rider to the side of the road and helps them get recollected.

Normalising reckless behaviour increases its social acceptability, and I think that as soon as it becomes widely known that you won’t go to jail for operating a motorcycle at double the speed limit, the first people to try this will be teenagers

So by treating the far more dangerous car behavior the same way, are we encouraging people to behave dangerously in cars?

But my point isn't that reckless behavior should be legalized, it's that cases where it's much more dangerous to society should be punished accordingly.