So, I'm pretty sure they're talking about the rental-scooters, not all scooters, which, peopel who tend to buy their own don't do these things... but....people get hurt on them, they increase accidents. People do stupid shit, like riding on sidewalks and trying to zip through pedestrians.
they get locked up all over the place, blocking sidewalks, entryways, bikeracks, etc.
in short the rental things are a massive nuisance,