AITA for making a nationaly charged joke in a diverse setting

So, this happened 12 years ago while I (30 M at the time) was on a business trip in Chicago.

For context (and it’s important for the story I promise) I’m from one of the Balkans countries and if there is one thing you can be sure about us collectively it is that we either “hate” our neighbours or joke about that hate. Our history is full of conflicts and wars so a huge chunk of humor is also derived from that history of conflict.

Back to the story…

At the time I was working for a US IT company which regularly brought in employees from our office to US to network with clients and push forward important projects.

I stayed in Chicago for 12 days and had a blast (museums, tourist attractions, NFL and basketball games, etc.) The company got out of the way to make sure they show me a part of the night life and I had really great time socializing with coworkers in the office

We arranged to even visit some places, play soccer in the park and do additional stuff after work.

While we were out for dinner/night out on a Friday in one trendy place (it was an old industrial complex where I tried a beer I loved and can’t find where I live – Left Hand Stout) 7 or 8 of us were hanging out and having a generally relaxed time.

One of the co-workers – let’s call her Ashley – (around my age) brought her fiancee (now husband) – let’s call him Angus – who everyone but me knew from before.

He was living in Chicago, but was originally from the UK.

While talking about growing up (I asked him where in UK grew up) he mentioned he lived in a small town in England (back in the in the late 80s or early 90s).

I responded by noticing that his first name was usually associated with Scottish heritage, so I assumed he might be from there.

He confirmed one of his parents was indeed Scottish and the one other Irish.

And that’s were I made my “joke” by (loud enough for everyone to hear) saying something like:

“Wait, you’re telling me that a guy with one Scottish parent, one Irish parent and a Scottish first name grew up in a small town in England?! You must have been bullied to hell!”

He found in hilarous (even spit a bit of his beer laughing) and confirmed it when he caught his breath.

The rest of the group (7 people ages 25 to 35) stopped talking and looked at me like I grew a new head. The conversation stopped for what seemed like an hour.

Someone from the group started saying something about it not being appropriate, but Angus cut him off (saying it was ok) and there was no mention of it for the rest of the evening. Which did end fairly quickly after that (about 25 to 30 minutes although it was not to late on a Friday night – cca. 10:30 PM).

Now, I can’t remember any other akward or strange moment out of the rest of my interactions, but after that night all those plans to visit places or go play soccer just disappeard one by one for the rest of my stay.

I continued working for that company for 2 more years, but that seemed strange, so WITA?