My dad's mom's family has a lot of ancestry from presbyterians from the north of Ireland. (Obvioisly I'm not irish and never will be, not one of those) I'm American
Still i'd like to visit next summer, but from what I've read... it seems still pretty sectarian over there... not something I'd like to deal with personally. Maybe just stay in the south and enjoy the sights there instead.
It’s fine, nothing at all to worry about. Like you said, you’re an American and that is how you will be viewed. Maybe avoid Mid-July so you don’t have to see the ugliness of Loyalism, when they do have their sectarian festival.
I’m curious what you’ve heard…
Nah, your friend is worrying over nothing, been watching too many movies maybe. Sure, how would anybody know if he’s catholic, as long as he’s not wearing his “I love the Pope” t-shirt? Look, you’ll see a lot of weirdo loyalists and an overabundance of union jacks in some places, but they’ve no interest in you. Likewise, catholic areas will have lots of interesting murals celebrating various anti-colonial struggles, you won’t find much overt sectarianism in those neighborhoods.
Leave the Pope t-shirt at home (I guess there’s no presbyterian equivalent?) and avoid the dodgy parts of town, you’ll have a great time. The Antrim coast and Mourne mountains are very beautiful, if you like a bit of nature!