The scooters and other cheap vehicles you cite are a separate problem from just being Lithium-Ion batteries. They're cheap procucts with bad electronics and poor protection of the battery. Gasoline powered products of such low quality would be similar fire hazards, if not worse.
Lithium-Ion batteries work fantastic for EVs. My 8 year old, 50k+ mile Leaf still has its origial battery and it still has 100% capacity. Something anti-Lithium-Ion FUD pushers told me was literally impossible.