Maybe, but maybe rapport based on “I don’t know you but I’ve heard your kind are a harmless lot who are always up for a drinking party after work”, is useful in a very limited set of circumstances, such as meeting a new team of peers, maybe. I’d still argue not, since the point of rapport building is to get to know the person in front of you, not how well they fit your preconception / stereotype.
In a large majority of situations in my experience, like being a senior manager of a new team, the CEO of a company meeting clients or negotiating with vendors and partners, it’s utterly irrelevant at best.
Also, the fact that Ireland has a major, major alcohol problem is no justification for the stereotype; so do many northern hemisphere countries. London had its Gin Crisis of the 18th century, with huge death toll and virtual breakdown of society, and the UK still has astronomical alcohol consumption, but they don’t get labelled the same way as the Irish