Not to be rude, but have you considered this may have been an issue with you and your attitude, rather than everyone you met, if even people who you seemed to think liked you couldn't stand you.
Anyway this conversation is a net negative to my day and I’m bowing out.
In my experience, the United States and England (not the entire UK) have the thinnest skin and some people will straight-up tell you to f-off home on the slightest criticism, especially on the subject of human rights or the expeditionary wars.
There are of course the usual suspects, the racists and "Pro-Irish" crowd, who will blame everything on immigrants and accept no criticism of their imagined Ireland, but this isn't true in general.
However, if you make grand pronouncements from a position of profound ignorance and overtly judge the life choices of your new compatriots - a speciality of the GP - you will find yourself alienated at best. This is true everywhere, not just Ireland.
Unless, of course, the criticism is someone making a personal observation about how they saw tipping culture expand during their time in Ireland, right? Then the appropriate response is to generalize that Americans love making ignorant comments about other cultures.
Unless they're factually incorrect, which is the case here.
Perhaps they just had a different experience than you.
There’s also another commenter in this thread who says they’ve lived in Ireland for their entire life and says they’ve experienced the same thing.
Then, there’s you.
There are two likely explanations I can think of for your behavior here. 1, you are arguing in bad faith. 2, you are unable, for whatever reason, to understand that others might have a different experience in the world than you.
In either case, I don’t see any point in continuing this conversation. Have a nice day.