“You have to be kidding....there was a hatred for Catholics and especially Irish Catholics in Massachusetts to the point where jobs ads were posted with “no Irish need apply” in newspapers and at the hiring companies.”
Urban myth.
http://www.amren.com/mtnews/archives/2005/03/ano_irish_need.php
Your own source states...Newspaper ads for women sometimes did include NINA, but Irish women nevertheless dominated the market for domestics because they provided a reliable supply of an essential service.
Newspaper ads for men with NINA were exceedingly rare.