Why Did Luke Call It a Laser Sword?

Luke wants to make Rey understand that everything beyond the apparatus itself is pure imagination, so he calls the lightsaber by a name that describes the device, but lacks context, to relativize her associations regarding the weapon. It's a bit like calling, say, Excalibur, an “old sword”.

Why does George Lucas call lightsabers laser swords?

I was just calling them laser swords because that's what you called them in your first draft of the original script when it was called 'The Adventures of the Starkiller: Episode I — The Star Wars. ' Because I'm your biggest fan, please take me back to Tatooine with you."

Who calls a lightsaber a laser sword?

In the 3rd episode of season one he tells Ezra "Having a laser sword doesn't make you a Jedi."