The big difference is in stability. Scooters are insanely unstable compared to bikes, for complicated reasons I don't fully understand, but I think have something to do with where the centre of gravity is, and how the geometry of the forks help force them into self-righting.
The danger scooters provide to their own riders is much higher than bikes. And because of this, I suspect riders are forced to spend a lot more attention on that, which means they have less attention to spare and are more likely to endanger others.
The big difference is in stability. Scooters are insanely unstable compared to bikes, for complicated reasons I don't fully understand, but I think have something to do with where the centre of gravity is, and how the geometry of the forks help force them into self-righting.
The danger scooters provide to their own riders is much higher than bikes. And because of this, I suspect riders are forced to spend a lot more attention on that, which means they have less attention to spare and are more likely to endanger others.