Because there are two types of riders. that fukk it up for everyone.
The teenage daredevils in the crotch rockets.
They commonly seen popping wheelies, doing annoying revs at red lights, driving 150 on the highway, and crashing out spectactorally. People are referencing this guy specifically when they say motorcycles are dangerous. They are if you ride like him.
Then there is the wannabe 1%er
This guy thinks the road belongs to him, and road rage on people trying to pass. knock off rearview mirrors if you cut him off. And drive by you giving you the finger. Commonly seen riding a harley and wearing leather. They are the biggest aholes on the road. He also has the extremely loud pipes that disturbs the whole neighborhood And they don't even wave to other bikers.
People with limited cognitive ability like to generalize in order to account for it, So they act like these two are all bikers, But its not.
There are two more.
The retired dad biker, known as the weekend warrior.
This guy only rides on sunny weekends around town. Doesn't bother anyone. doesn't go over the speed limit, just likes to get out and cruise sometime. If he could afford he'd be on a boat fishing instead. He just goes to the local bar once a week during the summer and then goes home.
and finally the every day commuter.
They just got a motorcycle because its more affordable than a car, and much better gas mileage. They are going to work or running errands. Not trying to show off or anything. They generally go the speed limit too. usually have quieter low cc bikes. because city traffic doesn't require a bike capable of breaking 200mphs
Only thing dangerous about them is sometimes you will see them riding in the rain or riding with a bunch of stuff loaded on the bike, because this is their primary mode of transportation. Not just a hobby. But otherwise they are super safe drivers and aren't bothering anybody or getting themselves killed.