Its amussing really. I would guess they are trying to clamp down on the potential for "MacGyvered" weapons on the plane. There are tons of potential ways people can engineer make shift weapons using stuff they can carry onto the plane and the authorities are clamping down on it. Chances are some politician saw the old "deoderant can and lighter flamethrower" idea somewhere and figured he couldn't ban deoderant and went with lighters instead.

You can see their perspective however, smoking doesn't occur on flights, so realistically its going to be a very small inconveniance to most people, and if it saves even one life it will be justified.

It really wouldn't surprise me if in the next 20 years carry on baggage was completely removed from airplanes and you'll just be allowed your wallet and papers with you.