Irish Americans

Even fellow Republicans criticized the GOP for the St. Patrick's Day message.
Whether it was the famine or political and religious persecution that brought these Irish families to America, as described on the tour, they were met with much discrimination -- one of which is reflected in their housing and economic opportunity.
I had to ask. How did the Irish get the reputation for being such heavy drinkers? Even my own father is derisive about it, and he's where my Irish heritage comes from. Malachy McCourt has a theory. (I knew he would.)