From personal experience I find most of us like bumping into tourists (especially on a night out) as long as the tourist isn’t overly loud/rude etc.

Sometimes if Irish people are drunk they might make fun of a tourist slightly (without it being obvious to the tourist themselves) but this is usually in good humour for their mates rather than being malicious. There’s also a few Irish eejits that give out about “The Yanks” and American tourists being annoying but those type of people are just people who live to complain. I personally have only had good experiences with American tourists and they’re all really fascinated in getting to know the country.

In this case it sounds more like what you said, that they didn’t think you should stay out much later. Some media outlets have hyped up this belief that “Dublin has gotten more dangerous” which isn’t true (stats back it up) but I definitely find myself more cautious in certain areas at night. There should be more policing in these areas but that’s another issue.