Why are Irish Catholic areas full of "White Trash"?

Not the Redneck White Trash either, its like theyre own type of White Trash. They hang Irish flags next to American flags, drink a lot, very loud, fight a lot, cops are always around locking people up, they litter, they urinate in public, theyre very racist towards minorites and outsiders. They have gangs... Now the problem with my area is(I live near NYC), a lot of Mexicans and Dominicans are moving in and the Irish youth are attacking them(they were known for attacking Blacks and Hispanics when they mixed at Public Schools as well)... they write "LEAVE OUR COUNTRY" and SP1C in graffiti.... it just seems most Irish areas are like this... the Irish also have a high incarceration rate.