I hate those damn things almost as much as bicyclists that need to do the same thing on a heavily traveled road and tie up a lane doing 15 MPH. Then when you finally get around the bastards, they pass you while you wait for the next red light, blow through the intersection and get in front of you again.
They're legally similar to a bicycle. They travel 15mph, which is about how fast many bicycles go. They're not any wider than a bicycle. So scooter riders should use the same common sense and laws that bicycles use, and should be just as easy to pass as a bicycle.
They must stay as far to the right as is safe to allow cars to pass them in their lane. Technically, drivers are supposed to maintain 3 feet of space when passing both bikes and scooters, but I've never seen a lane 9 feet wide, so that bit is nonsense. If the lane isn't wide enough for them to be passed safely, then they should "claim the lane", and move to the center to make it clear that it's not safe to share the lane with them.
Problems: (1) no helmet (2) rider should not have lane-split with the bus... that's a death wish. (3) rider kept swerving left & right. This would be just as unsafe if they were doing that on a bike.