Well... How could they even possibly translate "fire extinguisher" as "hand grenade"?! Even the most crappiest dictionaries will not tell them that "fire extinguisher" translates to "hand" grenade. The Chinese for fire extinguisher is "灭火器", and the Chinese for hand grenade is "手榴弹" - two completely different things. If those people had no education in English at all, then they should think twice about trying to translate something.
Yeah, the guy/girl who came up with "hand granade" might actually be pretty stupid.
I don't know any Chinese myself but if you don't know any English, translating from Chinese to English might not be as simple as to just look it up in the dictionary. Chinese is so different from English that I'm not surprised these kind of things happen. The Kanjis for "fire extinguisher" might acutally have something to do with hands and.. exploding things!
Also, YES! I got 1 point since erection was already a used joke.