Further, Spain is bound by a legal treaty they signed. The US never signed on to UNESCO but their stated policy is Spain’s wrecks are protected under Sovereign Immunity.
I have provided links, as has Raider.
What is the UNESCO Convention on Protection of Underwater culture heritage?
Recognizing that underwater cultural heritage is largely undervalued, the 2001 Convention provides a common legally binding framework for States Parties on how to better identify, research and protect their underwater heritage while ensuring its preservation and sustainability. Sep 22, 2023