[quote] [R126] so what made the Irish unwelcome, the Catholic Irish or Protestant or just being Irish in general?

It's a complicated matter.

The Americans broke from England, but at the same time they identified with the English, and shared their prejudices.

The Irish were considered to be at the bottom of the heap of the people of the four nations of the United Kingdom because they were a conquered nation within more recent historical memory--Scotland had joined the union with England willingly when James VI of Scotland became James I of England, and moved from Edinburgh to London. Wales had been conquered centuries ago, and the majority of the Welsh had joined the majority of English people in changing their religion from Catholic to Protestant when Henry VIII broke with the Church of Rome.

But the Irish had no reason to do since in Henry VIII's time they were not part of the Crown. England conquered Ireland under his daughter Elizabeth I, and then conquered it again under William III, and the English sent their own people overseas to maintain rule there--most Irish Protestants are descendants of those original settlers (known as "the Protestant Ascendancy"). But Ireland remained overwhelmingly Catholic, and it was the Catholics who suffered most from the Great Potato Famine in the 1840s, and who emigrated overseas.

When the Irish started coming to the US especially in the 1840s and after, they were treated as outsiders because most of them were Catholic, and the dominant religion of the United States was still Protestant, because the Thirteen Colonies had been settled primarily by the British and the Dutch. Moreover, when they emigrated they were dirt-poor, and to have any hope of making money at all some of the younger men formed gangs, which were seen as a huge problem in the mid nineteenth century. Already the longer-term families in the US viewed Catholics in general with great suspicion given the history of Catholic and Protestant rivalry in the UK, and the Irish were also seen as the poorest and the least educated of immigrants, and so were much despised.

The Scots were seen by the English and American establishments alike as better than the Irish, mostly because so many of the Scottish settlers were Presbyterians. They also had a stereotyped reputation for many positive characteristics, such as industry and thrift, that accorded well with the Puritan traditions on which the US was originally founded. The success of Scottish settlers like the Carnegies or the Livingstons was thus not as much resented as the success of Irish Catholics like the Kennedys and Fitzgeralds by the older settled US families on the East Coast.

Even in the last 75 years the anti-Irish prejudice has some strength in the US establishment. It was thought remarkable JFK could be elected president since he was the first non-Protestant to win his party's nomination, and keep in mind that Joe Biden is only the second! Apparently Joe Biden's mother still loathes the English because of the prejudice her family suffered from them.