The founding stock was legally exported to the U.S. They are totally legal to keep, breed, and sell in The U.S. My guess is their are animals available in Italy that I can not legally keep at my location.
Laws are different from country to country. Here the local wildlife is strictly protected - even many plants, such as the most common mosses.
If the origin of these animals is legal, there is no problem.
If you were in Italy, you would have problems with that.
For example, a couple of months ago, in a town near here, were seized several tortoises (common here Testudo hermanni), with complaint to court of the owner and very high fines.
To keep dartfrogs here, we need documents certifying the origin of frogs.