jimjim1
My HP laptop battery pack is rated at 58 Watt hours with an output voltage of 12 volts, so perhaps more akin to a motorcycle battery in that particular case. The entire pack is less than the size of two king size cigarette packs laid end to end and weighs less than 500 grams. Current laptop batteries are deliberately limited in capacity so as to remain compliant with air transport regulations and to provide longer service life. Alternative extended use battery packs are available with far larger capacities. These cannot legally be transported on an aircraft. I believe the current limit to be less than 100 Watt hours for lithium chemistry batteries.
You are absolutely correct in stating that most laptop computer batteries store less energy than a car battery. The point is that for any given size, they are very energy dense and can represent a hazard if misused or abused - just the same as a car battery. The exaggeration was intended to reinforce the point that lithium batteries pack a considerable punch in an innocuous appearing case or device.