Yes, there are more murders in the US and that's a problem. But why don't you just take the total murder count instead of the firearm murder count? You're skewing numbers, as there's obviously fewer firearms in Europe and Japan. There's plenty of knife murders in said countries though. Murder's murder, the killer will use what's available.
What?, i'm only arguing, i'm not saying that my country is better than yours,i'm only quoting facts. there are different cultures and i'm being repectful, i'm sorry if i didn't explain well, you all know that English is not my mother tongue.