Crimes (alleged) on the high seas have a very long history of being prosecuted under their own set of rules. Look into it, you may be surprised what is “normal”
What I believe you're referring to is piracy, not drug smuggling. The term is Hostis humani generis - or enemy of mankind.
There is a very long tradition of treating pirates as outside of all laws because pirates would murder and pillage in one jurisdiction or on the high seas and then sail away to another jurisdiction. So all nations had a duty to confront pirates. That is not to say that summary execution was considered normal - it happened, but typically pirates were captured and afforded some due process.
In the modern era this logic has been extended to terrorism and certain crimes against humanity like torture.
It has NOT been extended to encompass drug trafficking. If you're smuggling drugs from Venezuela to Trinidad, you really don't want to be detected, so you're not going to stop any random ship that you see and murder the crew and steal the cargo. The whole concept of the pirate as someone who is waging war on humanity with extreme violence and can't be effectively dealt with by the nation that is effected doesn't really apply neatly to this situation.
You could make the argument that because drugs are dangerous, and drugs can be transported anywhere, that drug traffickers are effectively enemies of humanity who are doing extreme violence in the same vein as terrorists and pirates. But that would be a novel argument, not, in any way, "normal".
