WTF $5/Gallon?

I'm always intrigued when someone tries to suggest that their name is the 'proper' name when it's different around the world.

Petrol was first used as a name for the refined spirit in 1892 when it was registered as a trade name, although it may even have derived from the French. In many countries the name in use derives from benzene or naptha. Gasoline is almost exclusively the name in North America only, which doesn't make it any more the 'proper' name than any other in common use, petrol, benzin, nafta.
there's nothing wrong with calling it petrol as a colloquialism but saying that petroleum is the proper word is simply wrong