Why the Irish Hate Hillbillies

St. Patty's day is a great day to celebrate the Irish.
And hate the hillbilly.
Why, you ask?
According to Wikipedia (which is pretty accurate as long as it isn't predicting the deaths of comedians), the term "hillbilly" is derived from a group of Scottish hill people who helped King William III invade Ireland. They were "billy's boys."
Hence the name: Hill... Billy.
Since Ireland is still green and not a huge mud pit, it can be assured that the hillbillies must not have been invited to stay long.