If you don't have an organization in EU, they can't sue you in the U.S. because it's allowed here. It's like the U.S. trying to sue local Amsterdam pot shop because they sell drugs to U.S. residents.
I have bad news for you: things like the Uniform Foreign Money Judgments Recognition Act exist which makes it possible to enforce foreign verdicts. Even if no such law applies, most US companies that do business with EU customers have by definition some assets in the EU even if only briefly (or else they couldn't charge them anything).
The US doesn't sue foreign pot shops because the sale happens abroad and they have decided to not bother with that but they absolutely could enacted such a law if they wanted. Who is there to stop them? The US actually does apply some of its laws abroad. Here is an example that is similar to yours https://www.insightcrime.org/news/analysis/as-us-prosecutes-...
Again, the problem is only enforceability. If they can't get hold of any money, a verdict is useless.
That's the point. If I run a US-based company and have 0 assets in X country, it doesn't matter. EU lawyers would also know this and also wouldn't bring it to court. It's just a waste of everyone's time.
I'm certainly not going to do anything If I get a summons from a random country due to some random law. Especially if it means nothing in the country I'm currently located in.
