system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it a legal requirement that you wear a seat belt, yet people are allowed to drive motorcycles?

Don't get me wrong, I don't hate motorcyclists or anything, it just kinda confuses me. Whether or not I am wearing a seat belt, I'm pretty much guaranteed to be safer in a crash than someone on a motorcycle. I know its a good idea to wear a seat belt and would even if it wasn't a law, but it seems weird that it is a law when the only real safety measure on a motorcycle is a helmet, which at 70mph is not likely to do shit.
gpt
In a car, wearing a seat belt will stop your from going through your windshield. If you were strapped to a bike, you're pretty much fucked because the entire weight of your bike is about to go head over heels with you. 

One will stop you from being squishy. The other ensures it.