That is obviously also gonna be a reason. But I could imagine that his staff feels more comfortable with Schengen as a zone with (usually) open borders and high infection rates rather than specifying single countries. The latter would probably be harder to keep up in courts.

FWIW, without making this political, I don't even think it's the golf resorts. US and UK have very close economical links, there's a lot of business traffic. Esp by wealthy people flying NYC-London regularly. I would rather think he didn't want to affect those. I can imagine a lot of his friends would've been angry if NYC-London gets shut down. Most visitors to his resorts in Europe will be from the continent anyway. But that's obviously pure speculation.

Dublin has pre-clearing[1] arrangements for entering the US so you can do all your checks in IE. Most of the US companies registered in Europe are in the RoI/UK, which could be reason for why they exclude it. Also whether this makes sense for "containing" is a different question.

If you have ever traveled to US via Dublin before you will never want to travel from another airport after.

[1] > Dublin Airport is one of only a handful of airports outside North America that offers a US Preclearance facility. The benefit is that having cleared USCBP, passengers arriving in the US are treated as domestic arrivals, allowing them to avoid immigration queues upon arrival and pick up their bags and go. https://www.dublinairport.com/flight-information/travelling-...