A Moped is a moped!! Are cars different in the US than they are in the UK (except in the US they use 3 times the gas)
You said "Legally"... legal is referring to a single country's restrictions. Every country differs.
Also, the same doesn't apply to cars. We wouldn't be argueing whether the car was too fast to be a car, now would we?
Me: "OMG MY CAR IS SO 1337, IT GOES 200 MPH!!!"
Wolftones: "Legally, thats not a car, thats a drag racer, n00b."