If Webster's work illustrated anything, it's that "English" should be renamed to "American." The English don't really speak what's in their own Oxford dictionary. ;)
Anthropocentrism doesn't help. Too many of our "standards" are really just recordings of organic usage, rather than tools for communication.
The same reason we have yellow traffic lights in the US: to make people feel good.
A simple delay between red and green performs the same function, but yellow makes people feel better while they break the law.