You are assuming that the motivation of the vandals is to protest the presence of the scooters because they dislike them. That is an unfounded assumption on your part. I don't know if you've ever been in a city or been a teenager, but generally vandals vandalize stuff because they enjoy doing so, not to make any kind of political statement.

You're also ignoring that many of the scooters are being stolen not vandalized, or the vandalism is part of the theft (ripping off the GPS unit so the scooter can't be tracked).

Besides nuisance/boon is not a binary switch. Even if the vandals were a handful of angry cranks who were annoyed by the scooters, that doesn't imply that the scooters aren't overall beneficial to the city.