I think you are taking this a bit too literally.
How I perceived the rule, is as such:
Any and all fights should be between pirates doing battle. There should never be an instance where someone is personally attacked (verbal abuse) or abused outside of the game (social media, etc.) for any reason.
If someone has broken the rules against you - go to the powers that be (Rare) and let them smite them.
(Also, if I was being really pedantic, you could argue that the ship is always on the waves - due to it being a water sailing vessel - and therefore, it is fair game at any point within the game.)
Now, do I agree that it is unbelievably frustrating for pirates to pilfer your goods / sink your ship while you're out exploring an island? 100%!! But that's also part of the game. You take risks.. otherwise everyone would just race to the nearest island, and anchor down at the first sight of trouble.