If a soverign nation enacts a law that any illegal boats in it's internal waters are found they can be siezed and scuttled.
Any country can create such laws and that law would be valid and not break international shipping laws.
Indonesia and several other pacifoc nations have such laws and have scuttled dozens of fishing boats encrouching on their internal waters.
Raab did not rule out any action to prevent illegal fishing from EU and other vessels, as such he has not ruled out sinking boats
My comment may be to the extremes of methods used but as he didn't rule it out or really say what we would or wouldn't do, what I typed is not incorrect