I agree that they should have jail time, but life in prison after not actually harming anyone physically? That's authoritarian and exactly what I was replying to in OP's comment.
What if the car exploded, hurting people nearby? What if there was a police canine in the vehicle that wasn't see, or someone crouching on the other side of the car out of sight? Throwing a molotov cocktail into a vehicle, in my opinion, should be charged as attempted manslaughter.